SAND82-2034, 'Rock-Mass Classification of Candidate ... · Rock-Mass Classification of Candidate Repository Units at Yucca Mountain, Nye County, Nevada Brenda S. Langkopf, Paul R.

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SANDIA REPORT SAND82-2034 Unlimited Release * UC-70Printed February 1986

Nevada Nuclear Waste Storage Investigations Project

Rock-Mass Classification ofCandidate Repository Unitsat Yucca Mountain,Nye County, Nevada

Brenda S. Langkopf, Paul R. Gnirk

Prepared bySandia National LaboratoriesAlbuquerque, New Mexico 87185 and Lvermore, California 94550for the United States Department of Energyunder Contract DE-AC04-760P00789

I

SF2900(8-8 1)

I

'Prepared by Nevada Nuclear Waste Storage Investigations (NNWSI) Pro-ect participants aa part of the Civilian Radioactive Waste Management

Program (CRWM). The NNWSI Project is managed by the Waste Manage-ment Project Office (WMPO) of the U. S. Department of Energy, NevadaOperations Office /DOE/NV>. NNWSI Project work is sponsored by theOf fice of Geologic Repositories (OCR of the DOE Office of Civilian Radio-active Wasten aaement (OCRWM).

Issued by Sandia National Laboratories, operated for the United StatesDepartment of Energy by Sandia Corporation.NOTICE This report was prepared as an account of work sponsored by anagency of the United States Government. Neither the United States Govern-ment nor any agency thereof, nor any of their employees, nor any of theircontractors, subcontractors, or their employees, makes any warranty, ex-press or implied, or assumes any legal liability or responsibility for theaccuracy, completeness, or usefulness of any information, apparatus, prod-uct, or process disclosed. or represents that its use would not infringeprivately owned rights. Reference herein to any specific commercial product,process, or service by trade name, trademark, manufacturer, or otherwisedoes not necessarily constitute or imply its endorsement, recommendation,or favoring by the United States Government, any agency thereof or any oftheir contractors or subcontractors. The views and opinions expressed here-in do not necessarily state or reflect those of the United States Government,any agency thereof or any of their contractors or subcontractors.

Printed in the United States of AmericaAvailable fromNational Technical Information ServiceU.S. Department of Commerce5285 Port Royal RoadSpringfield, VA 22161

NTIS price codesPrinted copy: A07Microfiche copy A01

2

SAND82-2034

Unlimited DistributionPrinted February 1986

ROCK-MASS CLASSIFICATION OF CANDIDATE REPOSITORY UNITSAT YUCCA MOUNTAIN, YE COUNTY, NEVADA

Brenda S. LangkopfSandia National Laboratories

NWSI Repository Performance AssessmentsAlbuquerque, NH 87185

and

Paul R. nirkRE/SPEC, Inc.

Rapid City, SD 57709

ABSTRACT

The Nevada Nuclear Waste Storage Investigations (WSI) Project,managed by the Nevada Operations Office of the Department of Energy, isexamining the feasibility of siting a repository for high-levelradioactive waste at Yucca Mountain, a tuff site on and adjacent to theNevada Test Site, ye County, Nevada. Between 1981 and 1983, four tuffunits were considered as potential units for emplacement of radioactivewaste. Two of the four units are above the water table: the welded,devitrified portion of the Topopah Spring Member of the Paintbrush Tuffand the zeolitized, nonwelded portion of the Tuffaceous Beds of CalicoHills. The other two units are below the water table: the welded,devitrified portion of the Bullfrog Member of the Crater Flat Tuff andthe welded, devitrified portion of the Tram Member of the Crater FlatTuff. In this study, available site-specific information fromdrillholes, supplemented by the needed information from tuff units atother locations, was used in conjunction with two rock-mass-classification systems to evaluate the relative excavation stability ofthese units. The two rock-mass-classification systems are the SouthAfrican Council for Scientific and Industrial Research ClassificationSystem developed by Bieniawski and the Norwegian Geotechnical InstituteClassification System developed by Barton. Two other tuff units locatedat Rainier Mesa on the Nevada Test Site, the welded portion of the GrouseCanyon Member of the Belted Range Tuff and the nonwelded Tunnel Bed 5,were also evaluated using these rock-mass-classification systems. Theselast two units were never considered as possible locations for wasteemplacement but were evaluated as a basis for comparison with YuccaMountain units because there are existing stable tunnels in the RainierMesa units. The welded, devitrified portion of the Topopah Spring Memberand the welded portion of the Grouse Canyon Member ranked highest instability; the welded, devitrified portion of the Bullfrog and thewelded, devitrified portion of the Tram ranked lowest.

i

'L. ,

ACKUOWLEDGMENT

S. Bauer and S. Sinnock provided helpful technical reviews of this report.B. Barnett provided helpful editing.

ii

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TABLE OF CONTENTS

1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . .

2.0 CANDIDATE UNITS FOR WASTE EMPLACEMENT . . . . . . . . . .

3.0 BRIEF HISTORY OF ROCK-MASS CLASSIFICATION . . . . . . . .

4.0 DISCUSSION OF THE CSIR AND GI ROCK-MASS-CLASSIFICATIOUSYSTEMS . . . . . . . . . . . . . . . . . . .. . . . .

4.1 CSIR Rock-Mass-Classification System . . . . . . . .4.2 NGI Rock-Mass-Classification System . . . . . . . .

5.0 APPLICATION OF THE CSIR AND NGI ROCK-MkSS-CLASSIFICATIOUSYSTEMS TO THE TUFF UNITS . . . . . . . . . . . . . . . .

.. .

.. .

.. .

.. .

Page

1

7.

11

13

1315

19

5.1 Strength-Related Properties . . . . . . . . . .

5.1.1 Strength of the Intact Tuff Units . . . .5.1.2 Stress Reduction Factor . . . . . . . . .

5.2 Joint-Related Properties . . . . . . . . . . . .

5.2.1 Rock Quality Designation . . . . . . . .5.2.2 Joint Sets . . . . . . . . . . . .5.2.3 Spacing of Joints.5.2.4 Joint Alteration . . . . . . . . . . . .5.2.5 Joint Roughness . . . . . . . . . . . . .5.2.6 Condition of Joints . . . . . . . . . . .5.2.7 Joint Orientation with Respect to

Emplacement Drifts . . . . . . . . . . .

5.3 Groundwater-Related Properties . . . . . . . . .

6.0 FINAL RESULTS OF ROCK-MASS CLASSIFICATION OF THE TUFFUNITS............... . . . .....

7.0 DRIFT SUPPORT REQUIREMENTS . . . . . . . . . . . . .

: :

.

.

.

.

.

.

21

2123

29

314047656973

77

82

87

95

103

107

115

125

. . . . .

8.0 APPLICABILITY OF THE CSIR AND 1GI ROCK-HASS-CLASSIFICATIOUSYSTEMS TO TUFF UNITS AT YUCCA MOUNTAIN . . . . . . . . . . . .

APPENDIX A PLOTS OF FRACTURE FREQUENCY AS A FUNCTION OF DRIFTINCLINATION FOR THE TUFF UNITS AT YUCCA MOUNTAIN . . . .

APPENDIX B SUMMARY OF AVAILABLE INFORMATION PERTAINING TOFRACTURE COATING AND FILLING FOR ALL THE TUFFUNITS EVALUATED . . . . . . . . . . . . . . . . . . . .

9.0 REFERENCES

iii

LIST OF TABLES

Table Title Page

1 Drillhole-Depth Intervals of the Candidate EmplacementUnits . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2 CSIR Classification System . . . . . . . . . . . . . . . . . 14

3 NGI Classification System .16

4 Categories of Intact-Rock Strength . . . . . . . . . . . . . 22

5 Uniaxial Compressive Strength of the ntact-Tuff Units . . . 25

6 CSIR Ratings for Strength of the Intact-Tuff Units . . . . . 27

7 NGI Ratings for the Stress Reduction Factor for theTuff Units .28

8 CSIR and GI Ratings of Rock Quality Designation forthe Tuff Units .37

9 Fracture-Set Orientations as Determined from Drillholes andDrifts Within the G-Tunnel Complex . . . . . . . . . . . . . 45

10 NGI Ratings for Joint Set Number (Jn) for theTuff Units. . . ... 48

11 Summary of Fracture Inclinations in the Topopah Spring . . . 49

12 Summary of Fracture Inclinations in the Calico Hills . . . . 50

13 Summary of Fracture Inclinations in the Bullfrog . . . . . . 51

14 Summary of Fracture Inclinations in the Tram . . . . . . . . 52

15 CSIR Ratings for Joint Spacing for the Tuff Units . . . . . 66

16 NGI Ratings for Joint Alteration (Ja) in the TuffUnits.. . 70

17 Planarity Information from Drillholes in the TopopahSpring . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

18 Planarity Information from Drillholes in the CalicoHills . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

19 Planarity Information from Drillholes in the Bullfrog . . . 73

20 Planarity Information from Drillholes in the Tram . . . . . 74

iv

LIST OF TABLES (Concluded)

Table Title

21 GI Ratings for Joint Roughness (Jr) for the Tuff Units

22 CSIR Ratings for Condition of Joints in the Tuff Units

23 The Effect of Joint Strike-and-Dip Orientations inTunneling . . . . . . . . . . . . . . . . . . . . . .

24 CSIR and GI Ratings of Groundwater for the Tuff Units

25 Final CSIR Classification Ratings for the Tuff Units .

26 Final GI Classification Ratings for the Tuff Units .

27 Summary of Qualitative Description of the Rock-MassClassification of the Tuff Units . . . . . . . . . . .

28 Estimates of Unsupported Roof-Span Width and Stand-UpTime Based on the Rock-Mass Classification of theTuff Units .. . . . . . . . . . . . . . . . . . . . .

29 Comparison of CSIR and NGI Ratings . . . . . . . . . .

pate

75

78

. . .

79

84

88

89

92. .

. . 96

. . . 105

V

LIST OF FIGURES

Figure Page

I Map Showing the Location of the Nevada Test Site, YuccaMountain, and G-Tunnel .2

2 Map Showing the Boundary of the Potential Surface Areafor the Underground Facility at Yucca Mountain and theLocation of Drillholes USW G-1, USW G-4, UE-25a#1,UE-25b#1H, USW GU-3, USW H-1, USW H3, and J-13 . . . . . . 3

3 Line Graphs of Uniaxial-Compressive-Strength Data forthe Tuff Units .24

4 Plot of the CSIR Rating for Uniaxial CompressiveStrength of Intact Rock with Inclusion of Data for theTuff Units . . . . . . . . . . . . . . . . . . . . . . . . 26

5 Plot of the NGI Stress Reduction Factor as a Functionof the Strength-to-Stress Ratio with Inclusion of Datafor the Tuff Units . . . . . . . . . . . . . . . . . . . . 30

6 Rock Quality Designation as a Function of Depth for theTopopah Spring Portion of U-25a#l, USW G-, USW GU-3,and USW G-4 . . . . . . . . . . . . . . . . . . . . . . . . 33

7 Rock Quality Designation as a Function of Depth forthe Calico Hills Portion of UE-25a#l, USW G-1, andUSW G-4 . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8 Rock Quality Designation as a Function of Depth for theBullfrog Portion of UE-25a#1, USW G, USW GU-3,and USW G-4 . . . . . . . . . . . . . . . . . . . . . . . . 35

9 Rock Quality Designation as a Function of Depth for theTram Portion of USW G-1, USW G-3, and USW G-4 . . . . . . . 36

10 Rock Quality Designation as a Function of Depth for theGrouse Canyon in Ul2gCB#1 and U12gCB#2, G-Tunnel . . . . . 38

11 Rock Quality Designation as a Function of Depth forUl2gRHP#1 .39

12 Contour Plots of Oriented Fracture Poles in theTopopah Spring, Bullfrog, and Tram from DrillholeUSW G-3/GU-3, Yucca Mountain . . . . . . . . . . . . . . . 41

13 Contour Diagrams of Grouse Canyon Fracture Poles fromU12gCB#l and U12gCB#2, G-Tunnel . . . . . . . . . . . . . . 43

vi

LIST OF FIGURES (Continued)

Figure Page

14 Contour Diagram of Fracture Poles from DrillholesU12gLH-1, U12gSH-l, U12gTC-2, U12gWHH-3A, U12gWHH-3,U12gWHH-2, U12gWHH-l, U12gHH-l, and the Laser Driftat G-Tunnel .43

15 Contour Diagrams of Grouse Canyon Fracture Poles fromthe Northwest and Northeast Ribs of the Rock MechanicsDrift . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

16 Plots of Fracture Frequency as a Function of DriftInclination and Drillhole for All Natural FracturesMapped in the Topopah Spring, Calico Hills, Bullfrog,and Tram . . . . . . . . . . . . . . . . . . . . . . . . . 57

17 Summary Plot of Bounding Fracture Frequencies as aFunction of Drift Inclination for All Natural Fractures inthe Candidate Tuff Units .59

18 Plots of Fracture Frequency as a Function of HorizontalDrift Bearing for U2gCB#l and U12gCB#2 for All NaturalFractures from the Grouse Canyon That Were Part of aFracture Set . . . . . . . . . . . . . . . . . . . . . . . 61

19 Plots of Grouse Canyon Fracture Frequency as a Function ofHorizontal Drift Bearing for the Northwest and NortheastRibs of the Rock Mechanics Drift . . . . . . . . . . . . . 62

20 Plots of Grouse Canyon Fracture Frequency as a Function ofDrift Inclination for Natural Fractures from Ul2gRMP#l . . 64

21 Plot of the Final CSIR Classification Ratings for theTuff Units . . . . . . . . . . . . . . . . . . . . . . . . 90

22 Plot of the Final NGI Classification Ratings for theTuff Units . . ... . . . . . . . . . . . . . . . . . . . . 91

23 Plan View of the Intersection of VDH#5 and VDH#6 inTunnel Bed 5 in the G-Tunnel Complex . . . . . . . . . . . 100

24 Photograph of the Pillar at the Intersection of VDH#5and VDH#6 in Tunnel Bed 5 in the G-Tunnel Complex . . . . . 101

A-1 Plot of Fracture Frequency as a Function of DriftInclination and Drillhole for the Fractures WithoutSlickensides in the Topopah Spring, Calico Hills,Bullfrog, and Tram .109

vii

LIST OF FIGURES (Concluded)

Figure Page

A-2 Plot of Fracture Frequency as a Function of DriftInclination and Drillhole Not Including Fractures withSlickensides or Hairline Fractures in the Topopah Spring,Calico Hills, Bullfrog, and Tram . . . . . . . . . . . . . 111

A-3 Plot of Fracture Frequency as a Function of DriftInclination and Drillhole for the Fractures NotIncluding Hairline Fractures for the Topopah Spring,Calico Hills, Bullfrog, and Tram . . . . . . . . . . . . . 113

B-1 Summary of Fracture Coatings and Fillings for theTopopah Spring Portion of U-25a#1, USW G-1(a), USWG-1(b), USW GU-3, and USW G-4 . . . . . . . . . . . . . . . 117

B-2 Summary of Fracture Coatings and Fillings for the CalicoHills Portion of UE-25a#1, USW G-1(a), USW G-1(b), andUSW G-4 .119

B-3 Summary of Fracture Coatings and Fillings for the BullfrogPortion of UE-25a#1, USW G-1(a), USW G-i(b), USW G-3, andUSW G-4 . . . . . . . . . . . . . . . . . . . . . . . . . . 120

B-4 Summary of Fracture Coatings and Fillings for the TramPortion of USW G-l(a), USW G-1(b), USW G-3, and USW G-4 122

B-5 Summary of Grouse Canyon Fracture Coatings and Fillingsfor Ul2gCB#1 and U12gCB#2 . . . . . . . . . . . . . . . . . 124

viii

1.0 INTRODUCTION

The Nevada Nuclear Waste Storage Investigations (NNWSI) Project,

managed by the Nevada Operations Office of the U.S. Department of Energy

(DOE), is examining the feasibility of siting a repository for high-level

radioactive waste at Yucca Mountain. Yucca Mountain is located on and

adjacent to the Nevada Test Site (NTS) in southwestern Nevada about 140 km

(85 mi) northwest of Las Vegas. Figure 1 shows the general location of

Yucca Mountain, and Figure 2 provides a detailed map (Mansure and Ortiz,

1984). The heavy line on Figure 2 indicates the potential surface

boundary* for the underground facility at Yucca Mountain.

Yucca Mountain consists primarily of layered volcanic tuff. Four

tuff units at Yucca Mountain were originally considered as potential

locations for a repository. They were (1) the welded, devitrified, non-

lithophysal portion of the Topopah Spring Member of the Paintbrush Tuff;

(2) the zeolitized, nonwelded portion of the Tuffaceous Beds of Calico

Hills; (3) the welded, devitrified portion of the Bullfrog Member of the

Crater Flat Tuff; and (4) the welded, devitrified portion of the Tram

Member of the Crater Flat Tuff. The first two units are above the water

table, and the last two are below it.

An activity called the "unit-evaluation activity" was completed in

1983. The purpose of this activity was to provide "a relative comparison

of the four potential emplacement horizons using existing data and codes,

supplemented by engineering and scientific judgment when necessary" to

identify "the one zone most suitable for repository placement" (Johnstone

et al., 1984, p. 1). This activity ranked the units at Yucca Mountain on

the basis of (1) radionuclide-isolation time, (2) allowable gross thermal

loading, (3) excavation stability, and (4) relative economics. The final

* The underground boundary for each tuff unit will differ. The boundary isdependent on such things as fault locations at depth, the continuity andthickness of each unit, and the alteration of the rock units.

1

Figure 1. Map Showing the Location of the Nevada Test Site,Yucca Mountain, and G-Tunnel

2

E160000 m E60000 In E570000 m

TpRE rpJ

WELI

RANGE ; 7~ ~~~~~

.I .< 0 XSTE

>i' w 41 z~~~~ U0-UE25bP IN

E IFOC 2e' <eA -. <

2 BVREQU OF . \ 3

I I~N "'H~t1FT

Z 0 6000 100001t BOUNDARY OF THE' _ - _ ' . s- POTENTtAL SURFACE AREA

l_ ~~~~~~~~BOUNDARY BETWEENO 100 2000 S00 ALLUVIUM AND ROCKt

E16OOo II El 70000 II E1720001n Et74000fn

Note: Drillholes USW G-3 and USW GU-3 were drilled approximately 30 m (100 ft)apart as part of a two-stage, coordinated drilling and geophysical log-ging program. USW GU-3 was cored in the unsaturated zone, and USW G-3was cored largely in the saturated zone. Because the holes are soclosely spaced, only the location of Drillhole USW GU-3 is shown.

Figure 2. Map Showing the Boundary of the Potential Surface Area forthe Underground Facility at Yucca ountain and the Locationof Drillholes USW G-1, USW G-4, UE-25a#1, UE-25b#1H, USWGU-3, USW H-1, USW H-3, and J-13 (odified from ansure andOrtiz, 1984.)

3

recommendation of the unit-evaluation activity, based upon all the

ranking factors, was that the Topopah Spring be selected as the target

unit.

Rock-mass-classification systems were one of the methods used in the

unit-evaluation activity to evaluate excavation stability. Generally,

these systems allow the rock properties and conditions from drillholes at

a planned site to be compared with similar information compiled and

categorized from existing underground facilities so that a relative

estimate of the excavation stability of the planned site can be obtained.

Several rock-mass-classification systems exist. The two rock-mass-

classification systems used in conducting a preliminary study of relative

excavation stability for the unit-evaluation activity were the South

African Council for Scientific and Industrial Research (CSIR) Classifica-

tion System developed by Bieniawski (1976) and the Norwegian Geotechnical

Institute (NGI) Classification System developed by Barton et al. (1974a).

The focus of this report is a subsequent, more detailed analysis of

the rock-mass classification of the tuff units at Yucca Mountain using

the CSIR and NGI systems. The unit rankings for rock-mass classification

presented in this report are not completely the same as those published

in the final report for the unit-evaluation activity, but they support

the recommendation of the Topopah Spring as the target unit.

In addition to the candidate emplacement units at Yucca Mountain, two

tuff units at G-Tunnel, the welded portion of the Grouse Canyon Member of

the Belted Range Tuff and Tunnel Bed 5, were evaluated using the above

classification systems. The tuff units at this location were evaluated

not because G-Tunnel is being considered as a repository site but because

G-Tunnel contains stable tunnels in rock similar to that of the tuff units

at Yucca Mountain. Thus, G-Tunnel provides a valuable analogy for evalua-

tions of drift stability at the proposed repository site.

The G-Tunnel complex is an existing system of tunnels located approx-

imately 433 m (1420 ft) beneath Rainier Mesa (Figure 1). Many of the

drifts at G-Tunnel have been in existence for several decades and remain

4

stable despite underground nuclear-weapons testing in the Grouse Canyon

Member of the Belted Range Tuff and in Tunnel Bed 5. Throughout the

remainder of this report, these tuff units will be referred to as the

"Grouse Canyon" and "Tunnel Bed 5."

The main purposes of this report are (1) to determine how the tuff

units at Yucca Mountain and those at G-Tunnel compare with other rock

units that have been evaluated using the CSIR and the GI systems; (2) to

determine how candidate waste-disposal units compare with each other and

with the rock units at G-Tunnel; (3) to obtain an estimate of rock-support

requirements for the units at Yucca Mountain; and (4) to compare the

support now used at the G-Tunnel complex with that suggested from this

rock-mass-classification study for the G-Tunnel complex.

5-6

2.0 CANDIDATE UNITS FOR WASTE EMPLACEMENT

Portions of four stratigraphic units at Yucca Mountain were considered

as candidate horizons for the disposal of radioactive waste and are the

focus of this study. The four formal stratigraphic units considered were

the Topopah Spring Member of the Paintbrush Tuff, the Tuffaceous Beds of

Calico Hills, the Bullfrog Member of the Crater Flat Tuff, and the Tram

Member of the Crater Flat Tuff. Restricted portions of the formal stra-

tigraphic units constituted the candidate zones for waste emplacement.

These restricted zones are referred to informally in this report as, from

top to bottom, the "Topopah Spring," "Calico Hills," "Bullfrog," and

"Tram." The portions of each of the formal units considered were selected

and delineated on the basis of physical properties measured from core

samples from Drillholes USW G-1 and UE-25a#l. (See Figure 2 for the

locations of these drillholes.) The properties considered in selecting

and delineating the units were uniaxial compressive strength, thermal

expansion, mineralogy, porosity, grain density, and thermal conductivity

(Lappin, 1982a; 1982b; 1982c). A. R. Lappin, who initially defined the

restricted depth intervals, also provided a brief lithologic description

of the restricted intervals. These lithologic descriptions were used in

conjunction with lithologic reports from the U.S. Geological Survey

(USGS) to define the depth intervals of the emplacement units in USW G-4,

USW G-3, and USW GU-3 (Spengler, 1982a; Scott and Castellanos, 1984).

(See Figure 2 for the locations of these drillholes.)

The Topopah Spring unit was described by Lappin as "the lowermost

densely welded, devitrified zone, underlain by the basal vitrophyre or

variable altered zone just above the basal vitrophyre, and overlain by

material containing more abundant lithophysae" (Lappin, 1982c, p. 6).

This tuff unit was further restricted to that portion having a litho-

physal content of less than 10%. To define this further-restricted unit,

it was assumed that the actual content of lithophysal pore space agrees

with the content reported in the lithologic logs from the USGS.

The Tuffaceous Beds were described as the zeolitized, nonwelded por-

tion of the Tuffaceous Beds of Calico Hills (Lappin, 1982a; Johnstone

7

et al., 1984). The Bullfrog was described as that portion of the Bull-

frog Member that is welded and devitrified (Lappin, 1982b). The Tram was

described as that portion of the Tram Member that is welded and devitri-

fied (Lappin, 1982b).

Table 1 shows the drillholes and depth intervals for the candidate

disposal units defined according to the descriptions given above. The

strength and joint-related properties used in classifying the candidate

emplacement units were restricted to values measured in core samples from

these hole and depth intervals. Groundwater-related information for the

units below the water table was taken mainly from hydrologic field tests

of Drillholes USW H-1, USW H-3, J-13, and U-25b#lH. Generally, the hy-

drologic information available was from larger depth intervals, of which

the restricted depth intervals were a portion. Because it was not pos-

sible to restrict the hydrologic data used as closely as the strength and

joint-related data, these hole and depth intervals are not listed in

Table 1.

8

lb I

TABLE 1

DRILLHOLE-DEPTH INTERVALS OF THE CANDIDATE EMPLACEMENT UNITS

Drillhole Identification

CandidateEmplacement Unit UE-25a@1 USH G-1 USW G-3/GU-3 USW G-4

Lower NonlithophysalPortion of theTopopah SpringMember (Topopah Spring)

Zeolitized NonweldedPortion of theTuffaceous Bedsof Calico Hills(Calico Hills)

Welded DevitrifiedPortion of theBullfrog Member(Bullfrog)

328.0 - 384.7 m(1076.0 - 1262.0 ft)779.7 - 817.2 m eleva

(2558.0 - 2681.0 ft elev)

402.3 - 545.3 m(1320.0 - 1789.0 ft)796.9 - 653.9 elev

(2614.4 - 2145.4 ft elev)

711.1 - 762.0 mc(2333.0 - 2500.0 ft)488.1 - 437.2 elev

(1601.4 - 1434.4 ft elev)

303.9 - 391.8 m997.0 - 1285.0 ft)1021.6 - 933.8 m elev(3351.6 - 3063.6 ft elev)

425.2 - 529.1 m(1395.0 - 1736.0 ft)900.3 - 796.3 m elev

(2953.6 - 2612.6 ft elev)

713.2 - 775.7 m(2340.0 - 2545.0 ft)612.2 - 549.7 m elev

(2008.6 - 1803.6 ft elev)

210.3 - 361.8 ( 690.0 - 1187.0 ft)1270.0 - 1118.5 m elev

(4166.5 - 3669.5 ft elev)

Npb

NPNPNP

616.3 - 776.0 (2022.0 - 2546.0 ft)864.0 - 704.2 elev

(2834.5 - 2310.5 ft elev)

338.9 - 394.1 m(1112.0 - 1293.0 ft)930.6 - 875.5 m elev

(3053.3 - 2872.3 ft elev)

434.0 - 537.1 m(1424.0 - 1762.0 ft)

835.6 - 732.5 m elev(2741.3 - 2403.3 ft elev)

772.4 - 816.9 a(2534.0 - 2680.0 ft)497.2 - 452.7 a elev

(1631.3 - 1485.3 ft elev)

%CI.0

Welded DevitrifiedPortion of theTram Member (Tram)

NAdNANANA

841.2 - 920.5 a(2760.0 - 3020.0 ft)484.2 - 405.0 elev

(1588.6 - 1328.6 ft elev)

800.1 - 910.7 a(2625.0 - 2988.0 ft)681.2 - 569.5 elev

(2231.5 - 1868.5 ft elev)

841.6 - 914.7 i(2761.0 - 3001.0 ft)

428.0 - 354.9 a elev(1404.3 - 1164.3 ft elev)

a. All elevations were calculated using drillhole-location information reported by Holmes and Narver, Inc. (1985).b. Not present (the zeolitized, nonwelded Calico Hills unit was not present).c. The Bullfrog unit may not be fully represented in Drillhole UE-25a81 because this drillhole does not completely penetrate the Bullfrog Member.d. No data available (Drillhole U-25at1 did not reach the Tram Unit).

3.0 BRIEF HISTORY OF ROCK-HASS CLASSIFICATION

Several people have contributed to the evolution of rock-mass-

classification systems. Many of the ideas advanced by these people have

been incorporated unchanged in later rock-mass-classification systems.

Terzaghi (1946) produced one of the first published approaches to

rock-mass classification. He provided a basis for designing underground

mined openings by giving guidelines for the type of steel sets that would

be needed as support. He assumed that a certain portion of the rock

surrounding an underground opening would collapse into the opening if not

supported and that the remainder of the rock would readjust to stable

conditions without support. Steel supports were designed to hold in

place that portion of the rock that would collapse into the opening if

not supported. The steel sets were not intended to prevent movement of

rock but rather to support the portion of the rock assumed to be unstable.

This approach is considered to be conservative. Today, the approach

normally used in designing mine support is to prevent rock movement by

using rock bolts, mesh, and shotcrete.

Lauffer (1958) developed the basic concept of "stand-up time," a

concept included in later classification systems. He defined stand-up

time as the average time it would take for an unsupported active rock

span to fail. An active unsupported rock span is defined as the width of

the tunnel or as the distance from an artificial support to the rock face

if this distance is less than the width of the tunnel.

Deere (1964) introduced the concept of Rock Quality Designation

(RQD). He defined RQD as the percentage equivalent of the total length

of core greater than 10 cm (4 in.) divided by the total length of the

cored interval. RQD is an indirect measure of the number of fractures

and the amount of softening or alteration in the rock mass. Because core

recovery depends in part on the recovery methods used, Deere specified

that RQD should be based only on core obtained under properly supervised

drilling conditions using a double-tubed core barrel of at least X size

(2.125 in. in diameter). RQD was used to divide rock masses into similar

11

groups. Although the RQD concept is useful in determining the relative

stability of underground openings, more recent classification systems

have been developed that consider additional rock characteristics.

Wickham (1972) developed the Rock Structure Rating (RSR) system.

This classification system was one of the first that considered several

rock characteristics. It uses the characteristics of the general area

geology, joint patterns, and groundwater conditions to rate the stability

of mined openings in various rock units. The ratings predicted using

these rock characteristics were correlated with actual mined openings to

provide theoretical estimates of the steel-rib support needed for rocks

with similar ratings.

Bieniawski (1976) developed the CSIR rock-mass-classification system,

and Barton et al. (1974a) developed the NI rock-mass-classification

system. These two classification systems were used to evaluate the

candidate emplacement units in this report and are discussed in more

detail in Section 4.

12

4.0 DISCUSSION OF THE CSIR AND GI ROCK-MASS-CLASSIFICATION SYSTEMS

The CSIR and GI rock-mass-classification systems were used to eval-

uate the candidate tuff units because both are based on numerous case

histories, both can easily be used to quantify rock-mass qualities appli-

cable to excavation stability, and both are directed toward the present

conventional support techniques of rock bolts, mesh, and shotcrete. These

two rock-mass-classification systems "are of particular interest because

they include sufficient information to provide a realistic assessment of

the factors which influence the stability of an underground excavation"

(Hoek and Brown, 1980, p. 34). Brief descriptions of both systems are

provided below.

4.1 CSIR Rock-Mass-Classification System

The CSIR rock-mass-classification system includes the following

parameters: Strength of Intact Rock Material, RQD, Spacing of Joints,

Condition of Joints, Groundwater Condition, and Orientation of Joints. A

value is assigned to each of these parameters using a table developed by

Bieniawski (Table 2). and the values are added to obtain a final classi-

fication rating called the Rock Mass Rating (RMR). Classification ratings

are linear and can range from -12 to 100, with a corresponding qualitative

description of very poor rock to very good rock. Four of the six param-

eters used to classify the rock are related to joint characteristics:

RQD, Spacing of Joints, Condition of Joints, and Orientation of Joints.

Seventy-five points can be attributed to the favorable properties of the

joints if all the joint characteristics are favorable (i.e., if the joints

are widely spaced joints, are oriented very favorably with respect to the

tunnel, and are characterized by lack of separation; have discontinuous,

rough surfaces; and have hard joint wall rock). If the joint properties

are unfavorable (i.e., if the joints are closely spaced, have soft gouge

greater than 5 mm, and are oriented very unfavorably with respect to the

drift), the RR is 79 points less than that for joints with favorable

properties. Joints are the major factor in this classification system.

Inadequate or unrepresentative joint data can easily result in unrealistic

rock-mass classifications.

13

TABLE 2

CSIR CLASSIFICATION SYSTEM

A. CLASSIFICATION PARAMETERS AND THEIR RATINGS

PARAMETER RANGES OF VALUESSrength o~ne-load For ims ow rangeStrength Po~n' bad > 8 UPS 4 -8 MPa 2 -4 UPa I 2 UPs -unra A compres

Of S.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~w test a Preferred.nlCl rock Un a.Mmate41 ComDttp'ss' > 200 MPs 100 -200 MPa 502 100 MPa 25 -50 un Pa UPa MPa

strength >_ 200_M____________Mpg25_-____M___________Up

Rating 15 12 7 2 1 0

Do coe qualty ROD 90 - 00% 75%0% 50% 75% 25% -50% < 25%

Rhtng 20 17 13 6 3

31 Spacing of tmis >3m 1 -3 n 0.3- 1 m 50 -300 mm C 50 mm

Ratinng 30 25 20 10 5aces urface~~~~~~~~~~s. R sda sr

Very rowgh surlaces SIghtlyroughsurlaces Sgnhti yroughsurlaCesl.Ck" d u-0Ce. Soit gouge > S mmth.c

Conddt-on of ponts Not contbnuous Sepaaton < 1 mm Separatbon < mm Gouge < 5 mm thCk OR4 No separtt on ORrd pet wll rock Sot ont wall rock A ont n > nu

Hard join wlrok ar on ltrc Soltnnwall rock JonIa open 1-5 mm 055 it

Ratng 25 20 12 a 0

nflow Per Om < 25 25 -125 > 125tunnel length N'one htrel/tyof 14tre5'mrt ~ne'~

'5z "I. OA OR OR OR

5 Glo Ratno or pnnej 0 0. 0.2 0.2 05 > 0.5

""' OR OR °- OOR ORMoist only Waler under Moderate Serere

General conditons Completely dry mntenstitral staru pressure waler p oen-s

Rating 10 O 4 0

S. RATING ADJUSTMENT FOR JOINT ORIENTATIONS

ormntt onS iop V eaourye Fa.uable Faw Unllrourable Ve 1`

Tnnels 0 -2 -5 -10 a

Rotngs FourdMIOo .* -7 .15 -25

sopes O .5 -25 -50 -60

C. ROCK MASS CLASSES DETERMINED FROM TOTAL RATINGS

Rating 100 l 8 dO- 61 60 41 40 21 <20

ClassaNo I s oil IV Vey rc

Oescrptron Very good rock Good ock Fatr rock Poor rock Very poor rock

0. MEANING Of ROCK MASS CLASSES

Class No I II 11 IV V

Coheson of the rock mane > 300 Ps 200 -30 Ps ISO 200 tPa 100 -150 Pa <100 Pa

Fmict-on angle o the rock mass > 45 | 40 -45 | 35- 40 | 30- 35 | < 30 |

Source: Bieniawski, 1976, p. 102.

14

4.2 GI Rock-Mass-Classification System

There are six parameters in the GI rock-mass-classification system.

They include (1) RQD; (2) Joint Set Number (J ); (3) Joint Roughness

Number (J ); (4) Joint Alteration umber (J ); (5) Joint Water Reduc-

tion Factor (J ); and (6) Stress Reduction Factor (SRF). A table devel-

oped by Barton et al. (1974a) (Table 3) is used to assign values to the

parameters for the rock units at Yucca Mountain. The parameters are

combined by using the following equation:

Q (RQD/J ) (Jr/Ja) (Jw /SRF)

where Q is the final classification value.

The GI system is logarithmic with possible Q values ranging from

0.001 to 1,000. The corresponding qualitative descriptions for these

endpoints are "exceptionally poor" to "exceptionally good." As in the

CSIR system, the nature of joints plays a major role. Favorable joint

properties (excellent RQD; massive, no or few joints; discontinuous

joints; tightly healed joints with hard, nonsoftening, impermeable

filling) are equivalent to a Q of 1,000* (J SRF), while unfavorable

joint properties (very poor RQD; crushed rock or earthlike material; no

rock-wall contact when sheared, and thick continuous zone or bands of

clay) are equivalent to a Q of 5 x 10 3* (Jw/SRF).

15

TABL 3

NGI CLASSIFICATION SYSTEM

1.

A.B.C.D.E.

2.

A.B.C.D.E.F.G.H.

I-

3.

ROCK QUALITY DESIGNATION

Very poor .....................Poor ..........................Fair ...........................Good .........................Excellent ......................

JOINT SET NUMBER

Massive, no or few joints ........One joint set ...................One joint set plus random .......Two joint sets .................Two joint sets plus random ......Three joint sets .................Three joint sets plus random .....Four or more joint sets, random,heavily jointed, sugar cube", etc.Crushed rock, earthlike ..........

(RQD)

0- 2525- 5050- 7575- 9090-100

(In)0.5-1.023469

12

1520

Note:(i) Where RQD is reported or

measured as 10 (including0) a nominal value of 10 isused to evaluate Q in Eq. (1)

(ii) RQD intervals of 5, i. c. 100,95, 90, etc. are sufficientlyaccurate

Note:(i) For intersections use

(3.0 x J)(ii) For portals use

(2.0 x J)

Note:(i) Add 1.0 if the mean spacing

of the relevant joint set isgreater than 3 m

(ii) Jr=r5 can be used forElanar slickensided joints

a vi ng lineations, providedthe lineations are favourablyorientated

JOINT ROUGHNESS NUMBER (.)

(a) Rock wall contact and(b) Rock wall contact before10 ms shear

A. Discontinuous joints ............B. Rough or irregular, undulating ...C. Smooth, undulating .............D. Slickensided, undulating .........E. Rough or irregular, planar .......F. Smooth, planar ................G. Slickensided, planar .............

(c) No rock wall contactwhen sheared

H. Zone containing clay minerals thickenough to prevent rock wall contact

J. Sandy, gravelly or crushed zonethick enough to prevent rock wallcontact ........................

4321.51.51.00.5

1.0 (nominal)

1.0 (nominal)

Table 2. Descriptions and Ratings for the Parameters a and 1,,

4. JOINT ALTERATION NUMBER (Ja)(a) Rock wall contact

A. Tightly healed, hard, non-soften- 0.75ing, impermeable filling i. e.quartz or epidote

B. Unaltered joint walls, surface 1.0staining only

C. Slightly altered joint walls. Non- 2.0softening mineral coatings, sandyparticles, clay-free disintegratedrock etc.

D. Silty-, or sandy-clay coatings, small 3.0clay-fraction (non-softening)

9'r (approx.)

(-) Note:(i) Values of ()r are in-

tended as an approxi-(250-350) mate guide to the

mineralogical proper-(250-300) ties of the alteration

products, if present

(200-250)

16

Z

TABLE 3 (continued)

E. Softening or low friction claymineral coatings, i. e. kaolinite,mica. Also chlorite, talc, gypsumand graphite etc., and smallquantities of swelling clays.(Discontinuous coatings, 1-2 mmor less in thickness)

(b) Rock wall contact before10 cms shear

F. Sandy particles, clay-free dis-integrated rock etc.

G. Strongly over-consolidated, non-softening clay mineral fillings(Continuous, < 5 mm in thickness)

H. Medium or low over-consolida-tion, softening, clay mineralfillings. (Continuous, <5 mm inthickness)

J. Swelling clay fillings, i. e. mont-morillonite (Continuous, < mmin thickness). Value of Ja dependson percent of swelling clay-sizeparticles, and access to water etc.

(c) No rock wall contactwhen sheared

K, L, Zones or bands of disintegratedM. or crushed rock and clay (see G,

H, J for description of clay con-dition)

N. Zones or bands of silty- or sandyclay, small clay fraction(non-softening)

O,P, Thick, continuous zones or bandsR. of clay (see G, H, J for descrip-

tion of clay condition)

4.0 (80.160)

4.0 (2S°-300)

6.0 (160-240)

8.0 (120 160)

8.0-12.0 (60-120)

6.0, 8.0or8.0-12.0

5.0

10.0, 13.0or13.0-20.0

(60-240)

(60-240)

S. JOINT WATER REDUCTION (Jw) Approx. waterFACTOR pressure

(kg/cm2)

A. Dry excavations or minor inflow,i.e. <S lImin. locally

B. Medium inflow or pressureoccasional outwash of jointfillings

C. Large inflow or high pressure incompetent rock with unfilledjoints

D. Large inflow or high pressure,considerable outwash of jointfillings

E. Exceptionally high inflow orwater pressure at blasting, de-caying with time

F. Exceptionally high inflow orwater pressure continuing withoutnoticeable decay

1.0 <1 Note:(i) Factors C to F are

0.66 1.0- 2 crude estimates. In-crease )w if drainagemeasures are installed

0.5 2.5-10.0 (ii) Special problemscaused by ice forma-tion are not con-

0.33 2.5-10.0 sidered

0.2-0.1 > 10.0

0.1-0.05 > 10.0

17

TABLE 3 (concluded)

6. STRESS REDUCTION FACTOR

(a) Weakness zones intersecting excavation,which may cause loosening of rock masswhen tunnel is excavated

A. Multiple occurrences of weakness zonescontaining clay or chemically disintegratedrock, very loose surrounding rock (any depth)

B. Single weakness zones containing clay, orchemically disintegrated rock (depth ofexcavation SO m)

C. Single weakness zones containing clay, orchemically disintegrated rock (depth of ex-cavation >50 m)

D. Multiple shear zones in competent rock(clay free), loose surrounding rock (any depth)

E. Single shear zones in competent rock (clayfree) (depth of excavation 50 m)

F. Single shear zones in competent rock (clayfree) (depth of excavation > 50 m)

G. Loose open joints, heavily jointed or "sugarcube" etc. (any depth)

(b) Competent rock, rock stress problems

(SR"

10.0

Note:(i) Reduce these values of

SRF by 25-50% if therelevant shear zones onlyinfluence but do not inter-sect the excavation

5.0

2.5

7.5

5.0

2.5

5.0

H. Low stress, near surfaceJ. Medium stressK. High stress, very tight

structure (Usuallyfavourable to stability,may be unfavourable towall stability)

L. Mild rock burst(massive rock)

ac/a7 at/If

> 200 > 13200-10 13-0.6610-5 0.66-0.33

5-2.5 0.33-0. 16

<2.5 <0.16M. Heavy rock burst(massive rock)

2.5 (ii) For strongly anisorropicl0 ostress field (if measured):0.5-2.0 when S1/9a3l 10, re-duce a and et to 0.8 t

and 0.8 at;when 51/ > 10, reduce ieand 6g to 0.6 ec and 0.6 atwhere: e unconfined

5-10 compression strength,all= tensile strength

10-20 (point load), a, and U3major and minor principalstresses

(iii) Few case records avail-able where depth of crownbelow surface is less than

5-10 span width. Suggest SRF10-20 increase from 2.5 to 5 for

such cases (see H)

5-1010-1S

(c) Squeezing rock; plastic flow ofincompetent rock under the influenceof high rock pressures

N. Mild squeezing rock pressure0. Heavy squeezing rock pressure

(d) Swelling rock; chemical swellingactivity depending on presence of water

P. Mild swelling rock pressureR. Heavy swelling rock pressure

Source: Barton et al., 1974a, pp. 194-196.

18

5.0 APPLICATION OF THE CSIR AND GI ROCK-MASS-CLASSIFICATION SYSTEMS TO THE TUFF UNITS

This section describes the information available to rate the tuff

units and discusses how a value was chosen for each of the parameters in

the CSIR and NGI rock-mass-classification systems. Each subsection in

this section discusses a particular classification parameter and is

followed by a "Ratings" table (see List of Tables). The tables summarize

the information available and list the numerical rating chosen for the

particular parameter for each tuff unit. In this section, the parameters

from both systems are ordered in three basic categories: strength-related

parameters, joint-related parameters*, and groundwater-related parameters.

Strength-related parameters are presented first and groundwater-related

parameters last.

The CSIR and GI systems each have one strength-related parameter.

The CSIR system groups values for strength of intact rock to associate

each group with a numerical rating. The uniaxial compressive strength

for each of the tuff units and the CSIR rating chosen for each unit are

described in Subsection 5.1.1. To rate competent rock, the WGI system

uses a ratio of the uniaxial compressive strength to the in situ stress.

The ratios are grouped and associated with a numerical rating called the

Stress Reduction Factor (SRF). The strength-to-stress ratio and the

associated SRF value of each of the tuff units are discussed in Sub-

section 5.1.2.

Both the CSIR and GI systems have numerous parameters for joint-

related properties. These parameters are discussed in Subsection 5.2.

In this subsection, the RQD values for the tuff units and the ratings

chosen are discussed first (Subsection 5.2.1). Both classification

systems use RQD. The CSIR system groups values for RQD and associates

each group with a numerical rating. The KGI system uses the actual value

* In this study, there is no differentiation between fractures andjoints. "Joint" is the term most commonly used in both the GI andCSIR systems to describe breaks in the rock. In this report, the twoterms are used interchangeably.

19

of RQD as the rating. The two remaining joint parameters, which are

reasonably quantitative, are discussed next. The GI parameter, Jn is

one of these (Subsection 5.2.2). This parameter associates a description

of number of joint sets to a numerical rating. The other reasonably quan-

titative parameter is the CSIR parameter, Spacing of Joints (Subsection

5.2.3). The CSIR system groups joint spacings and associates each group

with a numerical rating. The four remaining joint parameters are related

to qualitative descriptions of the joints. One of these is the NI param-

eter, Ja (Subsection 5.2.4). This parameter associates descriptions of

joint alteration (fillings and coatings of joints) with a numerical

rating. The next two qualitative parameters are partially based on the

information (i.e., faulting description) described in Subsection 5.2.4.

Movement along joints and descriptions of faults are used to quantify

joint roughness for the NG1 parameter, J (Subsection 5.2.5). Thisrparameter associates descriptions of joint roughness with a numerical

rating. The third joint parameter is the CSIR parameter, Joint Condition

(Subsection 5.2.6), which is based on several joint properties: rough-

ness, continuity, faulting materials, and hardness of the wall rock.

Descriptions that combine this information are associated with a numerical

rating. The CSIR system has one last joint parameter, which is in a cate-

gory by itself; in fact, Bieniawski separates it from the remainder of

the rock properties. This parameter is the Rating Adjustment for Joint

Orientation (Subsection 5.2.7), which combines information pertaining to

the in situ joint orientation with orientation of the engineered drift.

The relation between the two is assigned a qualitative description. This

description is then associated with a numerical rating.

The last category of parameters presented in this paper is the

groundwater-related properties. Both the GI and CSIR systems have one

parameter to rate groundwater. The systems provide several ways to n-

clude the effect of groundwater in the rock-mass-classification rating.

The CSIR groundwater parameter can be assigned a value based on inflow

per 10 m (33 ft) of tunnel length, on the ratio of the joint water pres-

sure to the major principal stress, or on a description of the general

groundwater conditions. The NGI system provides two main ways to rate

20

the groundwater: qualitative descriptions of the groundwater conditions

and approximate water pressure.

5.1 Strength-Related Properties

5.1.1 Strength of the Intact Tuff Units

One of five basic parameters in the CSIR system is strength of intact

rock. The property used to quantify intact-rock strength is uniaxial

compressive strength. The particular grouping of intact-rock strength

used in the CSIR system is similar to that originally proposed by Deere

and Miller (1966). As shown in Table 4, there are five strength cate-

gories. The categories in the CSIR system range from 1 to 25 MPa for

rocks of very low strength to more than 200 Pa for rocks of very high

strength. The corresponding CSIR rating for the intact-rock-strength

parameter ranges from 0 to 15.

The results of over 250 mechanical strength tests on tuffs from Yucca

Mountain tested at several different laboratory conditions have been re-

ported by Price (1983, 1984). The unconfined-compressive-strength (C )

values taken from these reports for the Bullfrog and Tram were tested

under the following conditions: full saturation, 236C, 10 /s strain

rate, and testing essentially perpendicular to bedding. For the Calico

Hills, the C values were tested under the following conditions: full

saturation, 230C, 10 3/s to 10 5/s strain rates, and testing essen-

tially perpendicular to bedding. For the Topopah Spring, the C values0

were tested under the following conditions: partial to full saturation,

230C, and 10 Is to 10 Is strain rates. All samples except two were

tested essentially perpendicular to bedding. The large majority of the

test specimens were right circular cylinders with diameters of 2.5 cm

(1 in.) and length-to-diameter ratios of approximately 2:1. Although the

Calico Hills and Topopah Spring are above the water table and are not com-

pletely saturated [the saturation of the Topopah Spring is about 65% and

that of the Calico Hills about 90% (Montazer and Wilson, 1984, p. 13)],

the strength results from saturated or wet samples were used because they

are generally lower than the strengths from dry samples (Hoek and Brown,

1980, pp. 153-154).

21

TABLE 4

CATEGORIES OF INTACT-ROCK STRENGTH

Categories from Deere and Hillera Categories

Point LoadStrength Index

(HPa)

from CSIR Systemb

DescriptionCo

(MPa)CO

(MPa) Rating

Very LowStrength

<27.5 For thislow range,uniaxialcompressivestrength ispreferred.

1 - 3 0

3 - 10 1

10 - 25 2

Low Strength

Medium Strength

27.5 - 55

55 - 110

1 - 2

2 - 4

25 - 50 4

50 - 100 7

High Strength 110 - 220 4 - 8 100 - 200 12

Very HighStrength

>220 >8 >200 15

a. Deere and Miller, 1966.b. Beniawski, 1976, p. 102.

The report by Price (1983, p. 23) includes C values for the Grouse

Canyon. The samples used in this study from that report were tested fully

saturated with strain rates ranging from 10 Is to 10 Is.

No published information is available for Tunnel Bed 5. The nine CO

results obtained from Teufel (1985) were based on tests of wet samples at

ambient temperature with strain rates from 10 4s to 10 5s. The re-

sults obtained from Holmes and Narver (1978) were from tests on samples

at ambient temperature and at approximately 907 saturation.

22

;

Line graphs of the information described above were developed for each

of the four rock units (Figure 3). From these data, the median, mean,

standard deviation, and the 95%-confidence interval on the mean were cal-

culated (Table 5). Recommended values for the unconfined compressive

strength of the matrix (imick et al., 1984, p. 2) and the standard devi-

ation (imick, 1984) associated with the recommended values are also

reported in Table 5. The recommended values, which include unpublished

information from additional drillholes, agree reasonably well with the

means obtained from analyzing the strength tests reported by Price (1983,

1984) for the four tuff units at Yucca Mountain.

The 95%-confidence interval on the mean was used to obtain a CSIR

rating for strength of intact tuff (Figure 4). These ratings are tabu-

lated in Table 6.

5.1.2 Stress Reduction Factor

One of the six basic parameters in the GI system is the Stress Reduc-

tion Factor (SRF). This parameter includes four major categories of

rock--swelling rock, squeezing rock, rocks with zones of weakness, and

competent rock. For swelling rock, squeezing rock, or rock with zones of

weakness that would intersect an underground opening, numerical values of

SRF have been developed on the basis of how particular features of rock

behavior influence drift stability; that is, qualitative descriptions of

the expected structural characteristics or deformational characteristics

of the rock determine quantitative values for SRF. However, for compe-

tent rock, numerical values of SRF have been correlated with the ratio of

the uniaxial compressive strength of intact rock to the overburden stress.

In essence, the SRF is a measure of "(1) loosening load in the case of

excavation through shear zones and clay bearing rock, or (2) rock stress

in competent rock, or (3) squeezing loads or swelling loads in plastic

incompetent rocks. It can be regarded as a total stress parameter"

(Barton et al., 1974a, p. 202). The tuff units at Yucca Mountain and in

the G-Tunnel complex are considered to be competent; therefore, the SRF

can be estimated on the basis of the uniaxial compressive strength and

the estimated overburden stress.

23

-

x x x x xx X XX x x xxxxxxx x

40 60 so 100 120 140 160 180 200 220 240 250COMPRESSIVE STRENGTH

(a) Topopah Spring

x x x x*W0nSMxx xx xx x x x x x x

10 1S .20 25 30 35 40 45 50 55

COMPRESSIVE STRENGTH

(b) Calico Hills

x Axxx IxW x x xx x x

20 30 40 50 60 70 80 90 100 110 120


(c) Bullfrog

)C x )C4OC x x x x x

40 50 so 70 go 90 100 110 120


(d) Tram

x x xx x x x x Xxx

5 10 15 20 25 30COMPRESSIVE STRENGTH

(a) Tunnel Bed 5

x x x xxx x x x

30 90 100 110 120 130 140 150.COMPRESSIVE STRENGTH

(f) Grouse Canyon

Note: The Xs denote strength measurements of individual samples.The mean value and the 95%-confidence interval are shown aboveeach line graph.

Figure 3. Line Graphs of Uniaxial-Compressive-Strength Data forthe Tuff Units (Derived from Price 1983, 1984; Holmesand Narver, 1978; Teufel, 1985.)

TABLE 5

UNIAXIAL COMPRESSIVE STRENGTH OF THE INTACT-TUFF UNITS

Standard Deviation andRecommended Mean Value

of Matrix CompressiveStrenxthStatistical Analysis

StandardNumber Median Mean Deviation

Drillhole of Tests (MPa2 (MPa) (MPa)

95% -ConfidenceInterval onthe Mean(MPa)

RecommendedaMean(MPa)

StandardbDeviation

(MPa)Tuff Unit

TopopshSpringc

USW G-1USW GU-3

26 157.0 162.3 55.6 139.8 - 184.8 171 58

Calico Hillsd USW G-1 37 23.7 26.6 8.5 23.7 - 29.5 27 9Ln

BullfroEd

Tramd

USW G-1

USW G-1

34

12

11

36.0

69.0

10.8

43.9

71.8

14.7

18.7

22.5

8.0

37.4 - 50.4

57.5 - 86.1

9.3 - 20.0

42 14

72 23

Tunnel Bed 5e NAf NA

Grouse Canyond 9 112.0 110.0 17.6 96.8 - 123.9 NA NA

a. Nimick et al. (1984, p. 2).b. Nimlck (1984).c. Derived from Price (1983, pp. 64-65) and Price (1984, p. 17).d. Derived from Price (1983, pp. 65-71).e. Derived from Holmes and Narver, Inc., (1978) and Teufel (1985).f. NA - Not available.

15I I

14 _

13

I I I

TOPOPAH SPRINGH

II II III

DUSE CANYON 4 P

00

t-

0

4

I-

zU.0

zw

(0

0U.

zF

0

12 -

GRI11

10 -

9 -

8

7

6 1-

5 _

4

3

2

I IBULLFROG I I

I I{ TRAM

I

M CALICO HILLS

Io '-4 TUNNEL BED 5

I .

1I I _ I I I

1 _

1 3 10 25 50 100 200 500

UNIAXIAL COMPRESSIVE STRENGTH, CO (MPa)

Note: The bars represent the range of C as grouped in the CSIRsystem. Their position on the y-axis indicates the associatedCSIR rating. The heavy arrows indicate the ranges of uniaxialcompressive strength used in classifying each tuff unit. Thedashed lines indicate the location of the endpoints of the rangesin the CSIR rating system for strength of intact rock.

Figure 4. Plot of the CSIR Rating for Uniaxial CompressiveStrength of Intact Rock with Inclusion of Data for theTuff Units

26

TABLE 6

STRENGTH OF THE ITACT-TUFF UNITSCSIR RATINGS FOR

Tuf fUnit

Topopah Spring

CoMean(HPa)

162 - 171

CSIRRating

for CO Mean

12

95%-ConfidenceInterval on

the Mean (HPa)

140 - 185

CSIR*Rating

12

Calico Hills

Bullf rog

Tram

Tunnel Bed 5

Grouse Canyon

27

42 - 44

72

4

4

7

2

12

24 - 29

37 - 50

2 - 4

4 - 7

58 - 86 7

15

110

9 - 20

97 - 124

1 - 2

7 - 12

*These are the CSIR ratingsof the tuff units.

used in the final classification (Section 6)

For an assumed average repository depth in each of the four tuff units

at Yucca Mountain, the overburden stress has been calculated using the

density of the stratigraphic column above each tuff unit. The calculated

overburden stresses (Johnstone et al., 1984, p. 9) are shown in Table 7.

The overburden stress in the G-Tunnel complex is based on in situ stress

measurements using an overcore technique (Zimmerman and Vollendorf, 1982,

p. 17). Using these overburden compressive stresses, the range of mean

uniaxial compressive strengths, and the 95%-confidence interval on the

mean for uniaxial strength from Table 5, the ratios of uniaxial compres-

sive strength to overburden stress were computed (Table 7). The strength-

to-stress ratios (using the ratios computed with the 95%-confidence in-

terval on the mean for uniaxial strength) were then used to assign an SRF

value for the various tuff units at Yucca Mountain and in the G-Tunnel

27

TABLE 7

NGI RATINGS FOR STRESS REDUCTION FACTOR FOR THE TUFF UNITS

Rating Based on Range ofMean Values of CO

Rating Based on 95%-ConfidenceInterval on the Mean

Tu ffUnit

AverageDepthm (ft)

overburdenStress

av(MPa)

Range

of MeanValues for

CO(HPa)

95%-ConfidenceIntervalon the

mean (a)CO

01v

NGI

RatingNGIRating

1.0*TopopahSpring

420(1378)

8.6 162 - 171 18.8 - 19.9 1.0 140 - 185 16.3 - 21.5

Calico Hills 495(1624)

10.3 27 2.6 9.8 24 - 29 2.3 - 2.8 10.9 - 9.2*

Co

Bullfrog

Tram

810(2657)

955(3133)

16.8 42 - 44 2.5 - 2.6

3.6

10.0 37 - 50

7.8 58 - 86

2.2 - 3.0 11.4 - 8.7*

2.9 - 4.3 8.9 - 6.1'20.0 72

Tunnel Bed 5 433(1420)

6.0 - 8.2 15 1.8 - 2.5 14.7 - 10.0 9 - 20 1.1 - 3.3 19.0 - 8.0*

Grouse

Canyon

433(1420)

6.0 - 8.2 110 13.4 - 18.3 1.0 97 - 124 11.8 - 20.7 1.0*

*These are the SRF values used in the final classification of the tuff units (Section 6).

4

complex. The SRF values, along with the SRF categories for competent

rock, are plotted in Figure 5. In those categories where a range of SRF

values corresponds to a range of strength-to-stress ratios, the SRF value

corresponding to a particular strength-to-stress ratio was semilogarithmi-

cally interpolated. Table 7 includes a list of the SRF values for each

tuff unit.

5.2 Joint-Related Properties

Two main types of USGS information, core index (CI) sheets and

fracture descriptions, were used to classify the fracture-related

properties of the tuff units at Yucca Mountain. USGS CI sheets were the

only information used to determine RQD for the Yucca Mountain units

described in Subsection 5.2.1 (Spengler, 1980, 1981, 1983a, 1983b, and

1983c).

The fracture descriptions provided by the USGS were the main source

of information used to assign appropriate ratings to the remainder of the

joint-related parameters in Subsections 5.2.2 through 5.2.6 (Scott and

Castellanos, 1984; Scott, 1983a, 1983b, and 1983c; Spengler, 1982b and

1982c). These descriptions include information on the fracture incli-

nation, planarity, and filling material. The joint descriptions are

usually limited to those portions of the core where the joints can be

fitted together. Therefore, it is assumed that the fracture frequencies

are not representative of heavily jointed or faulted areas. The USGS

took care to distinguish mechanically induced breaks from natural frac-

tures. Only the fractures that were reported as natural were used to

determine the joint spacing or frequency in this report. Naturally

induced fractures were usually defined as those fractures with a visible

coating or stain. Hairline fractures were also considered to be natural.

The fractures in core from Drillhole USW G-1 were described twice

(Scott, 1983b; Spengler, 1982c). In this report, the corresponding

descriptions are identified as USW G-l(a) and USW G-1(b). The differences

in the two sets of fracture descriptions do not significantly affect the

rock-mass classification of joints for the Yucca Mountain units.

29

20

15 HEAVY ROCK BURST(Massive Rock)

0

O ' \ 0 0 TOPOPAH SPRING0- CALICO HILLS

Z 0-@* * BULLFROG0 0---CO TRAMo 10 TTUNNEL BED 5D $\ GROUSE CANYON

enl ~ < sMILD ROCK BURST(Massive Rock)

5

LOW STRESSHIGH STRESS NEAR SURFACE

-VERY TIGHT STRUCTURE A

N)MEDIUM STRESS~~~~~~~~ --

1 2.5 5 10 20 50 100 200 500

RATIO OF UNIAXIAL COMPRESSIVE COSTRENGTH TO OVERBURDEN STRESS Co

Note: The heavy dark lines represent the relationship between C/crv andthe numerical values for the SRF as set by the NGI system. Thesymbols indicate the range of Co/av used in classifying eachof the tuff units and the corresponding value for SRF.

Figure 5. Plot of the NGI Stress Reduction Factor as a Functionof the Strength-to-Stress Ratio with Inclusion of Datafor the Tuff Units

30

A limited amount of information other than subsurface data from Yucca

Mountain was used to help classify the fracture properties of the Yucca

Mountain units in Subsections 5.2.2 through 5.2.6. Results from surface

mapping of fractures in similar units at Yucca Mountain, as obtained by

Scott et al. (1983, pp. 311-317), were also used. Where appropriate

information to classify fractures was lacking from USGS information

obtained at Yucca Mountain, observations and results from mapping of

fractures from similar units at G-Tunnel were used as a supplement

(Langkopf and Eshom, 1982; Krier, 1980; Eshom, 1981).

5.2.1 Rock Quality Designation

The parameter RQD is used in both the GI and CSIR systems. The CSrR

system groups values for RQD and associates each group with a numerical

rating. The GI system uses the actual value of RQD as the rating. RQD

was calculated for each cored interval using the information from the

Yucca Mountain drillholes (Spengler, 1980, 1981, 1983a, 1983b, and 1983c)

recorded on USGS CI sheets. Broken core, recovered core, lost core,

number of joints, and cored interval were recorded. Broken core is

defined as the footage of core that is less than 10 cm (4 in.) in length;

core loss is the unrecovered footage of core; and joints are the number

of joints measured in the cored interval. Ee (1983) defines CI as

[(broken core + core loss + 1/3 joints) + (cored interval ) x 100; (1)

Deere (1964) defines RQD as

[(sum of core lengths >4 in.) (cored interval) x 100. (2)

Using a portion of the information (cored interval, core loss, and broken

core) recorded to calculate CI, the RQD was calculated as

I(cored interval - core loss - broken core)

(cored interval)] x 100. (3)

31

The validity of using Cr information in this way is dependent on the

definition of broken core. If the core loggers follow the definition

given by Ege for the broken-core parameter in CI, the latter equation

should be valid for RQD. Deere (1964) specified several qualifications

for determining RQD: (1) the core used to determine RQD should be at

least X size, 2.125 in. in diameter; (2) the core barrel used should be

a double-tubed core barrel; and (3) core drilling should be supervised to

prevent unnatural breaks in the core.

A double-tubed core barrel was used to obtain core from the Yucca

Mountain and G-Tunnel drillholes discussed here. The diameter of most of

the core from Yucca Mountain ranged from 3.875 to 4.25 in. An excep-

tion is the Topopah Spring unit in Drillhole U-25a#l, for which NQ core,

1.875 in., was used to determine RQD. All the core used from G-Tunnel

was HQ core, 2.5 in. RQD is dependent both on the direction of drilling

and the skill of the driller. In general, the RQD values calculated are

expected to be conservative (i.e., the actual core may be more fractured)

because the hole was not drilled with the primary goal of obtaining the

most representative CI or RQD.

Figures 6 through 9 show RQD as a function of depth for each of the

four units at Yucca Mountain. The average RQD calculated for each unit

for each hole is shown on the figures. The range of average RQD values

for each unit was used to assign the appropriate rock-mass-classification

value(s) for each unit. Table 8 displays the range of average RQDs for

each unit and the assigned rock-mass-classification values.

The RQD for the G-Tunnel units in this report was calculated using

the original relationship defined by Deere. Figure 10 and a portion of

Figure 11 show RQD as a function of depth for the Grouse Canyon from

G-Tunnel. Figures 10(a) and (b) are for two nearly horizontal drill-

holes (200 from the horizontal), U12gCB#l and U12gCB#2. These drillholes

are approximately 0.3 m (1 ft) apart. The RQD plots for these nearly

horizontal holes are not significantly different from those for the Grouse

Canyon portion of Figure 11, the RQD plot for the nearly vertical

32

ROD ROD

689700

750

800

210 1

225

ia.

I

850

900 275

ROD xa.I.aw

wa

950

AVERAGEROD * 35.2

(a) UE-25a#1

1000

1050

1100

150

.300

.325

*350

ROD0 50 100

1112 - . 338.9

I 11150 I . 350

.l0I

1200 i

'I1150w

aIL I

II 83 .I * 360.6AVERAGEROD * 45.2

(c) USW GU-3

I

a.

i

a

. 375

1250 -r II

394AVERAGEROD * 79.7

1293 -

(b) USW G-1 (d) USW G-4

Note: In most cases, the endpoints of the unit were within a coredinterval. Therefore, because it was impossible to separate thedata so that they matched the endpoints of the unit, the endpointof the cored interval closest to the endpoint of the tuff unitwas chosen.

Figure 6. Rock Quality Designation as a Function of Depth for theTopopah Spring Portion of UE-25a#l, USW G-1, USW GU-3,and USW G-4 (Derived from Spengler, 1980, 1981, 1983a,and 1983c.)

33

ROD0 50 100, I a 401.1

ROD0 50 100Ii I j 432.21418

1450-

1500.

1550

zI-IL

0

1600-

zI-

aI

7100-rt 424.3

450

-1I I

500

-I

-25

] 537.7

AVERAGEROD * 98.7

1650'

1700.

1750'

1764-

: 46.8

AVERAGEROD-84.6 0.

E

x

0.BAao

Cc) USW G-4

(a) U-25a#1

i ..539 .1

AVERAGERQD 89.6

(b) uSw G-1

Note: In most cases, the endpoints of the unit were within a coredinterval. Therefore, because it was impossible to separate thedata so that they matched the endpoints of the unit, the endpointof the cored interval closest to the endpoint of the tuff unit waschosen.

Figure 7. Rock Quality Designation as a Function of Depth for theCalico Hills Portion of U-25a#1, USW G, and USW G-4(Derived from Spengler 1980, 1981, and 1983c.)

34

0 50 100ROD

0 50 1002331 * 710.5

725

-2400-

I X ~~~0

2450 750

2501 762.3

AVERAGEROD * 86.5

1 (a) UE-25a#1

617.5

625

650

675

700 ZI-a.

I

I.-a.hi

7250 50 100

2533 1 ' 772ROD

2550 -F

750

5073 3AVERAGE . 2600"RQO. a64.0

(c) 136W GU-3t 2450

'SILI-

1111

_ 775

LL

:AVERAGEROD 98.8

2650

---- r-i-' 7763

AVERAGEROD * 9.3

2677

(b) USW -1 (d) USW G-4


Figure 8. Rock Quality Designation as a Function of Depth for theBullfrog Portion of UE-25a#1, USW G-1, USW GU-3, andUSW G-4 (Derived from Spengler, 1980, 1981, 1983a, and1983c.)

35

- -

2760

2800

2850

ROD5'0 °8412

> i~850

ROD

xI.a.w

2900-

---- I

_I-a.

875

xI-

0.

875 E

zCIa.i.JM

ROD

2950 900

- 921.73024-

AVERAGEROD * 96.0

U5WG 'I

(a) USW G-1

z

a.a

ix

I-a.w

I 1 914.7AVERAGEROD * 78.5

(c) USW G-4

(b) USW G-3


Figure 9. Rock Quality Designation as a Function of Depth for theTram Portion of USW G-1, USW -3, and USW G-4 (Derivedfrom Spengler 1981, 1983b, and 1983c).

36

TABLE 8

CSIR AND GI RATINGS OF ROCK QUALITY DESIGNATION FOR THE TUFF UNITS

Range of Average RQD CSIR RGITuff Unit from Drillholes Rating Ratinr

Topopah Spring 35 - 80 8 - 17 35 - 80

Calico Hills 85 - 99 17 - 20 85 - 99

Bullfrog 64 - 99 13 - 20 64 - 99

Tram 78 - 96 17 - 20 78 - 96

Tunnel Bed 5 93 20 93

Grouse Canyon 37 - 51 8 - 13 37 - 51

(80- from the horizontal) drillhole, U12gRHP#l. This drillhole is located

76 m (250 ft) from Drillholes U12gCB1l and U12gCB#2. Figure 11 also con-

tains information for Tunnel Bed 5. There is a noticeable increase in

RQD at approximately 11.6 m (38 ft), which corresponds to the contact

between the Grouse Canyon Member and Tunnel Bed 5; that is, at depths

greater than 11.6 m (38 ft), the RQD is generally greater than it is for

depths less than 11.6 m (38 ft). The RQD plots fot the Grouse Canyon

are similar in appearance to those for the Topopah Spring, and the RQD

plot for Tunnel Bed 5 is similar in appearance to those for the Calico

Hills.

The range of the RQD averages from U12gRHP#1, U12gCB#l, and U12gCB#2

was used to assign rock-mass-classification ratings for the Grouse Canyon.

The average RQD in Ul2gRHP#1 was used to assign a rock-mass-classification

rating for Tunnel Bed 5. Table 8 displays the range of average RQDs for

these units and the assigned rock-mass-classification ratings.

37

ROD

RQD

0 50 100

20

.4-

I-

..w0

E

=

0

.I-

I-a.LI0

E

a

AVERAGEROD = 51

(a) U12SCB#1

AVERAGEROD 46

(b) U12gCB#2

Note: The total depth of the drillholes is in the Grouse Canyon Member.

Figure 10. Rock Quality Designation as a Function of Depth forthe Grouse Canyon in Ul2SCB#1 and U12SCB#2, G-Tunnel(Derived from Eshom, 1981.)

38

I

I

RQD

50 100

0.0

10.0

ROCK BIT USED, NO CORE

I-.

Id-C0

E-

Ix20.0GROUSECANYONMEMBER

30.0

38.0

38.0

11.6AVERAGERQD- 37

…- - - - - -T…

IZ-a.0

50.0 -

60.0 -

* I

IIiIi

- 11.6

15.0 E

=I0.wa

TUNNELBED 5

- 20.0

e #570.0

71.8 _ _ - .

AVERAGERQDr93

Note: The Grouse Canyon Member is 0.0 to 11.6 m (0.0 to 38.0 ft), andTunnel Bed 5 is 11.6 to 21.9 m (38.0 to 71.8 ft).

Figure 11. Rock Quality Designation as a Function of Depth forU12gRMP#1 (Derived from Langkopf and Eshom, 1982,p. 41.)

39

5.2.2 Joint Sets

One of the six parameters in the GI system is the Joint Set Number

(Jn). Descriptions of the number of joint sets (e.g., "Massive, no or

few joints,") are correlated with a numerical rating. In order to cor-

rectly determine the number of joint sets in a rock unit, it is necessary

to have information on the distribution of both the strike and dip of the

joints. The only information available for joint orientations at Yucca

Mountain comes from mapping of surface outcrops and analysis of oriented

core from vertical drillholes. Insufficient fracture-orientation infor-

mation is available from oriented core to adequately describe joint sets.

Figure 12 shows plots of the available fracture information from oriented

core obtained from USW G-3 and USW GU-3 (Scott, 1983d). In these figures,

the poles of the fractures are contoured on the lower hemisphere of a

Schmidt Equal Area Net. The plots are for the Topopah Spring, Bullfrog,

and Tram units. The data for the Topopah Spring unit include orientation

information for only 33 fractures, although 848 fractures were mapped

from core. The orientation data from the Bullfrog unit are for only 14

of the 635 fractures described. Orientation data from the Tram unit are

for only 4 of the total of 179 fractures that were described.

Because of the scarce amount of subsurface oriented-fracture data at

Yucca Mountain, available surface data from Yucca Mountain and subsurface

data from the G-Tunnel complex were used to estimate the number of joint

sets that might be expected at Yucca Mountain. Several surface traverses

were completed by Scott et al. (1983) at Yucca Mountain to determine frac-

ture attitudes and frequencies in the Tiva Canyon Member and the Tuffa-

ceous Beds of Calico Hills. The Tiva Canyon Member contains lithophysae

in places and is more welded than the Tuffaceous Beds of Calico Hills.

The Tiva Canyon Member has material properties that are similar to those

of the Topopah Spring. Five surface traverses were completed for the

Tiva Canyon Member at Yucca Mountain, and one surface traverse was com-

pleted for the Tuffaceous Beds of Calico Hills near the Prow (Figure 2).

Most of the mapped fractures were nearly vertical. Each fracture traverse

in the Tiva Canyon Member indicated the presence of one joint set,

40

I

(a) Topopah Spring (ib) Bullfrog

(c) Tram

Note: The fractures were plotted on the lower hemisphere of a SchmidtEqual Area Net. Thirty-three fractures were mapped for theTopopah Spring; fourteen fractures were mapped for the Bullfrog;and four fractures were mapped for the Tram.

Figure 12. Contour Plots of Oriented Fracture Poles in the TopopahSpring, Bullfrog, and Tram from Drillhole USW G-3/GU-3,Yucca Hountain (Derived from Scott, 1983d.)

41

generally striking NOOW to 300W. In a couple of traverses, the strike

was east of north (approximately N101). Fracture strikes for the

surface traverse in the Tuffaceous Beds of Calico Hills indicated the

presence of at least two joint sets: one oriented just west of north

(approximately 5W) and the other approximately N600W. Scott et al.

(1983) mapped few random joints (random joints are joints that do not fit

in a dominant pattern) in the surface traverses of the Tiva Canyon Member

and the Tuffaceous Beds of Calico Hills.

Fracture information from the Grouse Canyon in the G-Tunnel complex

was also used to obtain an estimate of the number of joint sets that might

be expected at Yucca Mountain. Figures 13(a) and 13(b) are contour plots

of the fractures mapped from core from Drillholes U2gCB#1 and U12gCB#2.

The fractures in these drillholes were mapped by shom (1981). The poles

of the fractures for these holes were plotted on the lower hemisphere of

a Schmidt Equal Area Net and then contoured in 2% intervals. Fracture

sets were arbitrarily defined as concentrations greater than or equal to

4% of the fractures. The nearest 2% contour was the limiting boundary

for these concentrations. The centroid of the orientations within the 21

contour was visually estimated to determine an approximate orientation

for each fracture set. On the basis of these criteria, Drillhole U2gCB#1

exhibits three fracture sets plus random joints,* and Drillhole U2gCB#2

displays four fracture sets plus random joints. Table 9 contains a list-

ing of the fracture-set orientations shown in the Schmidt Equal Area Net

and the number and percentages of fractures associated with each fracture

set.

* A joint classified as random may actually be a part of a joint set witha large regular spacing. Because of the large spacing between thejoints, the random joint may be overshadowed by a joint set with a muchsmaller spacing. To a limited extent, the classification of joints asrandom is dependent on the sample size, sample orientation, and analysisscale (i.e., the definition of the concentration of joints large enoughto constitute a set). Joint sets that have a large regular spacing maybe placed in the random category if the sample size is too small or thedefined analysis scale is large. The region surrounding rooms andpillars in the emplacement area is the scale of interest here.

42

S

(a) Ul2gCB#l (b) U12gCB#2

Note: The fracture poles are plotted on the lower hemisphere of a Schmidt

Equal Area et. The fractures are from the welded portion of the

Grouse Canyon Hember. One hundred fifty-six fractures were mapped for

U12gCB#l. One hundred twenty-nine fractures were mapped for U12gCB#2.

Figure 13. Contour Diagrams of Grouse Canyon Fracture Poles from

Ul2gCB#1 and U12gCB#2, G-Tunnel (Derived from Eshom, 1981.)

Note: The fracture poles are plotted on the lower hemisphere of a Schmidt

Equal Area et. Eight hundred seventy-six fractures were mapped.

Figure 14. Contour Diagram of Fracture Poles from DrillholesU12gLH-1, U12gSH-1, U12gTC-2, U12gWHH-3A, U12gWHH-3,

U12gWHH-2, U12gWHH-1, U12gHH-1, and the Laser Drift at

G-Tunnel Krier, 1980.)

43

Similar criteria were imposed on a summary of fracture-orientation

information from several drillholes and a drift Drillholes U12gLH-1,

U12SSH-l, U12gTC-2, U12SWMH-3A, U12gWMH-3, U12gWHH-2, Ul2gWMH-1, U12gHH-l,

and the Laser Drift) in the same area to determine the number of fracture

sets. The fractures were mapped and plotted on the lower hemisphere of a

Schmidt Equal Area Net by rier (1980). This plot, shown in Figure 14,

indicates the presence of two fracture sets plus random joints. Table 9

lists the fracture-set orientations and the number and percentages

associated with each fracture set.

The above criteria were applied once more to joints mapped by shom

(Langkopf and shom, 1982) in the Rock Mechanics Drift at the G-Tunnel

complex. This drift is approximately 76.2 m (250 ft) from the drillholes

discussed above. Joint data for the northwest side of the drift were

plotted separately from those measured on the northeast side of the drift.

The Schmidt Equal Area Net plots are shown in Figures 5(a) and 15(b).

The plot of the northwest side of the drift indicates that there are two

fracture sets plus random joints. The plot of the northeast side indi-

cates that there are three fracture sets plus random joints. A listing

of the fracture-set orientations and the number and percentages associ-

ated with each fracture set are also shown in Table 9. The random joints

in the Grouse Canyon are a significant portion (25.6 to 55.0%) of the

total number of joints mapped.

The above information was used to assign NGI descriptions for the

endpoints for the Jn rating for the Topopah Spring, Bullfrog, and Tram

to "two joint sets plus random" and "three joint sets plus random." The

assigned descriptions were based not only on the joint-set information

presented above but also on the fact that the Topopah Spring, Bullfrog,

and Tram units generally have strengths and numbers of fractures similar

to those in the Tiva Canyon Member and the Grouse Canyon. More weight

was given to the G-Tunnel fractures because this information was obtained

underground at a depth of 433 m (1420 ft) (Langkopf and Eshom, 1982,

pp. 11-12).

44

TABLE 9

FRACTURE-SET ORIENTATIONS AS DETERMINED FROMDRILLHOLES AND DRIFTS WITHIN THE G-TUNNEL COMPLEX

Drillholeor Drift

Fracture-SetOrientation

Number ofFractures

Percentage ofTotal Fractures

U12gCB#1 N30-E, 69-SEV25-E, 6-SEN60-W-N71-W. 80-SW-85-NERandom joints*

N43-E, 75-SEN19W, 78-NEN60W, 78-SW-84-NEHorizontalRandom joints*

35173965

22.410.925.041.7

U12gCB#2 125261571

9.34.0

20.211.655.0

Laser Driftand

AssociatedDrillholes

Northeast Sideof RockMechanicsDrift

Northwest Sideof RockMechanicsDrift

N29-E,N40-W,N72-W,Random

80-NW-80 SE850-SW78-NEjoints*

30398

106369

34.611.212.142.1

N78-W, 81-SWNW74E, 85-SEN35-E, 74-SEN51-W-N55-W, 86-SW-85-NERandom joints*

N32-E-N36-E, 79-E-80-WN64-W-N65-W, 86-S-82-NRandom joints*

811462847

5. 77.9

32.820.033.6

427440

26.947.425.6

*These joints did not fit into any of the dominant patterns for aparticular Schmidt Equal Area Net. The addition of the percentage ofthese joints with those in sets will sum to 100..

Jn ratings corresponding to the NGI descriptions of "two joint sets

plus random' and "three joint sets plus random" were also assigned to the

45

N

(a) Northwest Rib (b) Northeast-Rib

Note: The contours are plotted on the lower hemisphere of a SchmidtEqual Area Net. One hundred fifty-six fractures were mapped fromthe Northwest Rib. One hundred forty fractures were mapped fromthe Northeast Rib.

.

Figure 15. Contour Diagrams of Grouse Canyon Fracture Poles fromthe Northwest and Northeast Ribs of the Rock HechanicsDrift (Derived from Langkopf and shom, 1982, pp. 31-34.)

46

ib

Grouse Canyon. The number of joint sets assigned to the Grouse Canyon

was based solely on the information obtained from drifts in the G-Tunnel

complex.

The joint spacing was so large, or conversely, the fracture frequency

so small, both on the surface and in the subsurface in the Tuffaceous

Beds of Calico Hills, that this unit could be associated with the GI

description, "massive, no or few joints." (See the following subsection

for a discussion of joint spacing.) Tunnel Bed 5, which also has a large

joint spacing, was also assigned a value that corresponded to a

description of "massive, no or few joints."

The Joint Set umber description and corresponding UGI Jn rating

assigned to each of the units at Yucca Mountain and G-Tunnel are

summarized in Table 10.

5.2.3 Spacing of Joints

One of the five parameters in the CSIR system is Spacing of Joints.

Ranges of joint spacing are correlated with a numerical rating. In this

subsection, the inverse of joint spacing, joint frequency, is discussed.

Joint frequency is reported (1) as a volumetric fracture frequency

(number of fractures per cubic meter) and (2) as the number of fractures

per meter as a function of angle in a predefined plane. In this study,

the volumetric fracture frequencies were determined for comparison with

published frequencies (Scott et al., 1983). The linear fracture fre-

quency was determined for use in assigning a value to the CSIR parameter,

Spacing of Joints. Although one number may be used to represent the

volumetric fracture frequency for a rock mass (because it is essentially

a nondirectional parameter), the linear fracture frequency (fractures per

meter) is dependent on orientation, and a single value cannot be specified

that represents the rock mass. The linear-fracture frequency is the most

useful type of fracture frequency for use in the CSIR system because the

fractures of most interest are those that may intersect the drifts.

The first step in determining both types of fracture frequencies was

to group the fracture inclinations reported for each drillhole and unit

47

TABL1 10

JOINT SET NUMBER cJn) FOR THE TUF? WITSNGI RATINGS FOR

Tuff Unit

Topopah Spring

Calico Hills

VGIDescrIption of Joint Sets

2 Joint Sets + Randomto 3 Joint Sets + Random

Massive, No or Few Joints

NGI Ratinx

6 - 12

0.5 - 1.0

Bullfrog 2 Joint Sets + Randomto 3 Joint Sets Random

2 Joint Sets + Randomto 3 Joint Sets + Random

6 - 12

6 - 12Tram

Tunnel Bed 5 Massive, No or Few Joints 0.5 - 1.0

Grouse Canyon 2 Joint Sets Randomto 3 Joint Sets + Random

6 - 12

in 10- intervals (0-10, 10-20, 20-30, etc.). In this report, "incli-

nation" means the angle between a horizontal plane and the fracture. It

was assumed that all the fractures within each interval are parallel and

part of a discrete set. Tables 11 through 14 show the percentage of

mapped fractures in each 10- interval for each unit for each drillhole.

Despite the fact that the drillholes are vertical, the largest percentage

of observed fractures is nearly vertical (60 to 900).

The second step in determining both types of fracture frequencies was

to determine the number of fractures that would exist along a line per-

pendicular to each fracture set. This number represents the maximum

number of fractures that could occur in any direction and is commonly

called "the true fracture frequency." The number of fractures in each

10- interval for each drillhole and depth interval was recorded. The

midpoint of each 10- interval and the number of observed fractures were

48

Drillhole

USW G-1(a)

e0 USW G-1(b)

USW GU-3

USW G-4

UE-25a#1

0-10

9.4

1.4

11.8

1.2

11.9

SUMMARY

Percentage of

10-20 2O-Ao

10.4 5.7

11.3 5.6

9.2 6.1

23.2 13.4

11.9 7.7

TABLE 11

OF FRACTURE INCLINATIONS

Mapped Fractures in Each

30-40 40-50 50-60

7.6 3.0 6.2

5.6 2.8 5.6

4.7 3.5 5.8

11.0 9.7 15.8

4.9 2.1 5.6

IN THE TOPOPAH SPRING

10' Interval

60-70 70-80 1

5.7 18.3

11.3 19.7 I

9.8 21.7

11.0 6.1

11.2 27.3 1

30-90

33.8

36.6

27.4

8.5

L7.5

Volumetric FractureFrequency

1/m3 (1/ft3)

29.90(0.85)

4.54(0.13)

34.43(0.97)

4.45(0.13)

11.86(0.34)

TABLE 12

SUMMARY OF FRACTURE INCLINATIONS I THE CALICO HILLS

Drillhole

USW -1(a)

0 USW G-l(b)

USW GU-3

USW G-4

UK-25a#1

0-10

0.0

40.0

UP*

0.0

5.9

Percentage of

10-20 20-30

10.0 0.0

0.0 0.0

UP UP

0.0 7.9

3.9 0.0

Mapped

30-40

0.0

0.0

up

5.3

2.0

Fractures

40-50

0.0

0.0

UP

2.6

7.8

in Each

50-60

10.0

0.0

UP

28.9

11.8

10- Interval

60-70

0.0

20.0

UP

15.8

17.6

70-80

50.0

20.0

UP

31.6

21.6

80-90

30.0

20.0

UP

7.9

29.4

Volumetric FractureFrequencyI/m3 (ft3)

0.67(0.02)

0.16(0.004)

UP

1.43(0.04)

2.23(0.06)

*UP = Not present (the zeolitized nonwelded Calico Hills unit was not present).

I

'I

.1

1.1I-'

TABLE 13

SUMMARY OF FRACTURE INCLINATIONS IN THE BULLFROG

Percentage of Mapped Fractures in Each 10' Interval Volumetric FractureFrequency

Drillhole 0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 /rm3 (ft 3 )

USW G-l(a) 24.1 6.8 3.4 6.8 0.0 0.0 13.8 17.2 27.6 2.62(0.07)

USW G-l(b) p.O 11.1 0.0 11.1 0.0 0.0 11.1 55.6 11.1 0.67(0.02)

USW GU-3 7.1 4.9 4.7 6.9 10.2 12.4 17.8 22.2 13.7 17.11(0.48)

USW G-4 3.4 3.4 3.4 5.1 5.1 5.1 11.9 27.1 35.6 9.45(0.27)

UE-25a#l 0.0 3.0 3.0 19.4 23.9 9.0 20.9 17.9 6.0 4.26(0.12)

TABLE 14

SUMKARY OF FRACTURE ICLIUATIOUS I THE TRAM

Percentaxe of Mapped Fractures in Each 10- Interval Volumetric FractureFrequency

Drillhole 0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 i/M3 (/ft 3)

USW G-l(a) 8.4 11.3 8.4 11.3 4.2 2.8 5.6 18.3 29.6 5.28(0.15)

USW G-l(b) 18.8 16.7 4.2 2.1 0.0 2.1 10.4 22.9 22.9 3.16(0.09)

USW G-3 4.1 5.6 5.1 3.6 4.6 5.1 9.1 19.8 34.0 12.34(0.35)

USW G-4 8.6 8.6 5.7 2.9 5.7 2.9 12.8 12.8 40.0 6.85(0.19)

UK-25a#1 MA* NA NA VA UA NA HA UA KA NA

.,

*UA Uo data available (Drillhole UE25a#1 did not reach the Tram unit).

*

used in the following relationship to determine the true fracture

frequency:

Xt(4) - F(cos )(T) (4)

where

Xt(+) is the true fracture frequency for a given inclination

interval,

* is the midpoint angle of the inclination interval,

F is the number of mapped fractures, andmT is the thickness of the candidate emplacement unit in a

given drillhole.

The calculation of true fracture frequency is described in detail by

Terzaghi (1965). Calculation of true fracture frequency becomes less

accurate as the fracture inclination approaches that of the drillhole. A

"blind zone" occurs when the fracture orientation is parallel to the

drillhole. Because most of the reported fractures in each interval are

nearly parallel to the drillhole (i.e., most of the fractures have

inclinations of 60 to 90-), they fall into the blind zone. Terzaghi

recommends disregarding any joints that are within 20 to 30- of the

drillhole when information is available from other drillholes or from

outcrops at other orientations. However, in this study, the joints

nearly parallel to the drillhole were used because vertical drillholes

provide the only site-specific subsurface information for the Yucca Moun-

tain tuff units. Information from G-Tunnel is used later in this report

to try to provide an estimate of the ratio between fracture frequencies

from a vertical drillhole and the observed fracture frequencies in a

nearly horizontal drift.

If the true fracture frequencies for all 10- intervals are summed and

the fracture frequencies are expressed in units of fractures per meter,

the result is an estimate of the number of fractures in a sphere with a

diameter of 1 m. The following equation was used to normalize the sum of

53

3the true fracture frequencies to a unit volume of 1 m which has a

diameter of 1.24 m:

X Xt 1.24] (5)

where

Xv is the normalized volumetric fracture frequency in units of

1/nm and

Xt is the sum of the true fracture frequencies for the inclination

intervals within a particular unit and drillhole in units of 1/m.

The results of this calculation for each unit and drillhole are shown

in Tables 11 through 14. The volumetric fracture frequency for the

Topopah Spring ranges from 4.45 to 34.43 fractures/m3 (0.13 to 0.97

fracture/ft3); for the Calico Hills, the range is from 0.16 to 2.233 3

fractures/m (0.004 to 0.06 fracture/ft ); for the Bullfrog the range

is from 0.67 to 17.11 fractures/m3 (0.02 to 0.48 fracture/ft3 ); and

for the Tram the range is from 3.16 to 12.34 fractures/m3 (0.09 to 0.35

fracture/ft 3).

Scott et al. (1983, pp. 313-316) calculated volumetric fracture fre-

quencies on the basis of surface traverses in the Tiva Canyon Member and

the Tuffaceous Beds of Calico Hills. In the short traverses, where the

outcrops were continuous, they found that the volumetric fracture fre-3 3quency ranged from 6 to 8 fractures/m (0.17 to 0.23 fracture/ft ) in

the Tiva Canyon Member; in the long traverses, where the outcrops were

discontinuous, the volumetric fracture frequencies ranged from 2 to 4

fractures/rn (0.06 to 0.12 fracture/ft ). In this study, the volu-

metric frequencies for the Topopah Spring are close to the range reported

for the Tiva Canyon, with the exception of USW G-l(a) and USW G-3; the

values for Drillholes USW G-l(a) and USW G-3 are significantly higher

than those reported for the surface traverses in the Tiva Canyon Member.

The volumetric frequency for the Tuffaceous Beds of Calico Hills, based

on one surface traverse completed near the Prow (Figure 2 shows the loca-

tion of the Prow), was 1.2 fractures/m3 (0.03 fracture/ft3) (Scott et

al., 1983, p. 316). This volumetric frequency determined by Scott et al.

54

at the surface for the Tuffaceous Beds of the Calico Hills agrees well

with the volumetric fracture frequencies of drillholes calculated in this

study for the Calico Hills.

The true fracture frequencies determined for each 10- interval (Equa-

tion 4) in a particular drillhole were used to obtain fracture frequency

as a function of drift inclination. The following general relationship,

published by Hudson and Priest (1979, p. 341). was used to obtain fracture

frequencies for various drift inclinations:

n--D -Ji cos hi (6)

where

)D is the fracture frequency along the drift,

)iis the fracture frequency of the ith set, and

i is the acute angle between the drift and the normal to the ith

set.

The specific relationship used for the vertical drillholes at Yucca

Mountain was of the form

Tf(T) X cos - 8) + 2 cos(T - 75) + 3cos(-65)

+ ). cos( - 55) +-X cos(T - 45) + cos( - 35) (7)4 56

+ .7 cos(T - 25) + cosVt - 15) + cos(T - 5)

where

Tf(T) is the total number of fractures along a drift at a particular

inclination,

Y is the inclination of a drift,

). is the fracture frequency of those fractures with an inclination

of 5, and

X2 is the fracture frequency of those fractures with an inclination

of 15-, etc.

55

Because the fracture frequencies for the vertical drillholes at Yucca

Mountain have no associated strike, it is possible to plot fracture fre-

quency as a function of drift inclination in one plane. Such plots were

created for each drillhole and unit for several categories of fractures:

all fractures; fractures excluding only hairline fractures; fractures

excluding slickensides and faults; and fractures excluding both hairline

fractures and slickensides and faults. The hairline fractures and the

slickensides and faults were separated from the remainder of the frac-

tures because it was thought that their existence might be occasional or

random rather than part of a set. The plots that included all fractures

were not significantly different from those that excluded hairline frac-

tures and slickensides and faults. The plots of all fractures were used

to rate the joint spacing of the units [Figures 16(a), 16(b), 16(c), and

16(d)]. The remaining plots are shown in Appendix A.

On all of these plots, the fracture frequency at 90 represents the

uncorrected fracture frequency (i.e., the number of observed fractures in

a particular drillhole divided by the unit thickness for that particular

drillhole). The uncorrected fracture frequency (in fractures per mter)

for all fractures from the Topopah Spring unit ranges from approximately

1 to 6, those for the Bullfrog unit from approximately 0.2 to 4, those

for the Tram unit from approximately 0.7 to 1.8, and those for the Calico

Hills unit from approximately 0.1 to 0.4. The figures from Yucca Houn-

tain indicate that changing the inclination of the drift by 0 to 200 does

not significantly affect the number of fractures intersected by the drift.

Figure 17 is a summary of Figures 16(a), (b), (c), and (d). It

includes only the limiting fracture-frequency curves for each of the

Yucca Mountain units. The fracture frequencies clearly indicate that the

Topopah Spring is the most fractured and the Calico Hills the least frac-

tured. The abundance of fractures in the Topopah Spring, Bullfrog, and

Tram places all three of these units in the same category for Jn (Sub-

section 5.2.2).

56

o

t 8 z = z~~~~~~US GU-3

... .-----------------------------.._-............................

z

USW G-4 USW. G-1(b)-.-

- c~.. ................... ......... ~ -

-- -.,nn R0.0 90.00.O D0.0 20.0 30.0 40NC ON (DGru

DRIFT INCLINATION (Degrees)

(a) Topopah Spring

C.,-% tji

S._

oc

aC 8.-

90.00.0 1O.0 20.0 30.0 40.0 50.0 60.0DRIFT INCLINATION (Degrees)

(b) Calico Hills

Note: The cale along the ordinate changes in Figures 16(a) and (b).

Figure 16. Plots of Fracture Frequency as a Function of Drift Inclinationand Drillhole for All Natural Fractures apped in (a) TopoPshSprinl and (b) Calico Hills (Derived from Scott 1983a, 1983b,1983c and Spengler 1982b, 1982c.)

57

q

S I

_.-' CD

t

C

0

o

USWI U-3I I~~~~~G

........................... \

UE-25a#1

- - - _ *

US------ --- -*

USW ----------; ,t - .).

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0DRIFT INCLINATION (Degrees)

80.0 90.0

(c) Bullfrog

qC

.

0

: q

rz

co

cI

w

Eo

0.0 10.0 20.0 30.0 4010 50.0 80.0DRIFT INCLINATION (Degrees)

70.0 80.0 90.0

(d) Tram

Note: The scale along the ordinate changes in Figures 16(c) and (d).

Figure 16 (concluded). Plots of Fracture Frequency as a Function of DriftInclination and Drillhole for All Natural Frac-tures Mapped in the (c) Bullfrog and (d) Tram(Derived from Scott 1983a, 1983b, 1983c andSpengler 1982a, 1982b.)

58

0

4)

G O

z

rZ4

0

0

LUto

0.0 10.0 20.0 30.0DRIFIr

40.0 50.0 60.0INCLINATION (Degrees)

70.0 80.0 90.0

Figure 17. Summary Plot of Bounding Fracture Frequencies as a Function of Drift Inclination forAll Natural Fractures in the Candidate Tuff Units

It was necessary to make two assumptions in the analyses that deter-

mined fracture frequencies for the units at Yucca Mountain. One was that

the fractures mapped in the vertical drillholes (the only source of in-

formation available for this study) could be used to approximate fracture

frequencies for nearly horizontal drifts. Because the correction for

fracture frequency is not very reliable when mapped fractures are nearly

parallel to the drillhole, an understanding of the influence of this

assumption on the estimation of fracture frequency is particularly impor-

tant for two reasons: (1) repository drifts at Yucca Mountain are likely

to be nearly horizontal and (2) there are a large number of nearly ver-

tical fractures at Yucca Mountain. The second assumption was that frac-

tures with similar inclinations were part of a fracture set. Not only

the inclination but also the strike of the inclinations is important in

determining fracture frequencies. An understanding of the influence of

this assumption on the fractures that might be encountered during reposi-

tory construction is also important.

To better understand the effect these assumptions might have on this

study, information from the G-Tunnel complex was used to compare fracture

frequencies predicted from inclinations reported in vertical drillholes

and fracture frequencies predicted by using orientation information from

nearly horizontal drillholes and drifts. The joint sets and number of

fractures reported in Subsection 5.2.2 for the Rock Mechanics Drift and

Drillholes U12gCBA1 and U12gCB#2 were used to determine fracture frequen-

cy as a function of horizontal drift bearing.

Figures 18 and 19 show plots of fracture frequency vs. horizontal

drift bearing. Equation 6 was used to determine data points for these

plots. The Schmidt Equal Area Net was used to determine the angle be-

tween a horizontal drift and the various joint sets described previously

(Table 9). These angles were determined for every 20- of horizontal

drift bearing (i.e., 18 points were used to create Figures 18 and 19).

These plots, which do not include fractures classified as having random

orientation, predict a fracture frequency of approximately 2 to 3.5

60

T

; CC I

0.0 60.0 120.0 180.0 240.0 300.0

BEARING OF A HORIZONTAL DRIFT (Degrees)

(a) U2gCB#l

0

z

0*

t 4

C

0.0 80.0 120.0 180.0 240.0 300.0

BEARING OF A HORIZONTAL DRIFT (Degrees)

(b) U12gCB#2

Note: All fractures that were part of a set were used.

Figure 18. Plots of Fracture Frequency as a Function of HorizontalDrift Bearing for U12gCB#1 and Ul2gCB#2 for All aturalFractures from the Grouse Canyon That Were Part of aFracture Set (Derived from Eshom, 1981.)

61

Q1-1 *r-1d)

4- A4):2,-, g

41-01

U 9Zra:D 5

9W4 42riseWI= 3

t;4 9I%r.. I

0.0 MO 10. 1800 40.0 30.oBEARING OF A HORIZONTAL DRIFT (Degrees)

(a) Northwest Rib

-

9W IV

.as

[4

'-. A~

on

t= g

C;y£

CQCT

0.0 80.0 120. 180.0 400 30X00BEARING OF A HORIZONTAL DRIFT (Degrees)

(b) Northeast Rib

Note: All fractures that were part of a set were used.

Figure 19. Plots of Grouse Canyon Fracture Frequency as a Functionof Horizontal Drift Bearing for the Northwest andNortheast Ribs of the Rock Mechanics Drift (Derivedfrom Langkopf and shom,.1982, pp. 31-34.)

62

fractures/m for the Rock Mechanics Drift. If the fractures classified as

random [approximately 30. of the fractures are random (Table 9)] are

added to this figure, the fracture frequency becomes approximately 3 to

4.5 fractures/m. The plots for Drillholes U2gCB#1 and Ul2gCB#2 predict

a joint frequency of approximately 1 to 2.5. If the fractures classified

as random [approximately 50 of the fractures are random (Table 9)] are

added to this figure, the joint frequency becomes approximately 1.5 to

4 joints/m.

The fracture frequencies from the nearly horizontal drillholes and

Rock Mechanics Drift were compared with those predicted in the Grouse

Canyon portion of Drillhole U2gRHP#1. This drillhole has a nearly ver-

tical inclination (approximately 80- from the horizontal). As for the

vertical drillholes at Yucca Mountain, only fracture inclinations were

available in U2gRHP#l. Because U12gRMP#1 is not vertical, a measured

fracture inclination of 50- in this drillhole would be either 40 or 60-

in a vertical drillhole. To account for both possibilities of inclina-

tions, and to bound the possible values for fracture frequency, two cases

were considered to estimate fracture frequency in Drillhole Ul2gRMP#1:

(1) the fractures were inclined in the same direction as that of the

drillhole and (2) the fractures were not inclined in the same direction

as that of the drillhole.

The same procedure used to determine fracture frequency as a function

of drift inclination for the Yucca Mountain drillholes was used to deter-

mine that for Drillhole Ul2gRHP#l. Figure 20 shows thefracture frequency

as a function of drift inclination for U12gRHP#l. The fracture frequen-

cies for a horizontal drift range from approximately 5 fractures/m (if it

is assumed that the fractures are not inclined in the same direction as

that of the drillhole) to approximately 13 fractures/m (if it is assumed

that the fractures are inclined in the same direction as that of the

drillhole). Fracture frequencies for a horizontal drift are 3 to 4.5

fractures/r (based on information from the Rock Mechanics Drift in which

U12gRHP#1 is located). This analysis indicates that the fracture fre-

quency, based on fracture inclinations reported from vertical drillholes,

may overestimate the true fracture frequency found underground by a

factor of slightly greater than 1 to approximately 4.

63

0-4.

4)0

: Cs

-

z

c0

tEq

In

Wo

0.0 10.0 20.0 30.0 40.0 50.0 80.0 70.0 80.0 90.0DRIFT INCLINATION (Degrees)

Note: One curve is based on the assumption that fractures are inclinedin the same direction as that of the drillhole; in the othercurve, it is assumed that the fractures are not inclined in thesame direction as that of the hole.

Figure 20. Plots of Grouse Canyon Fracture Frequency as a Functionof Drift Inclination for Natural Fractures from U12gRHP#l(Derived from Langkopf and shom, 1982, pp. 49-52.)

64

Because of the large range of fracture frequencies indicated for most

of the Yucca Mountain units, upper and lower bounds were assigned to the

parameter for joint spacing. The above analysis indicated that pre-

dicting the underground fracture frequency from fracture-inclination data

will probably result in an overestimation of the true fracture frequency.

For this reason, the largest fracture frequency for a horizontal drift

(Figure 16) for each of the candidate units was reduced by a conservative

number of 30%. This value was used as the upper bound for fracture fre-

quency. The lower-bound fracture frequency for each of the candidate

units was approximated by the minimum fracture frequency for a horizontal

drift. The upper- and lower-bound fracture frequencies were the basis

for assigning ratings for CSIR joint spacing to each of the units (Table

15). The joint frequencies used as values for the CSIR joint spacing for

the Grouse Canyon were based on U12gCB#l and the Rock Mechanics Drift.

Joint frequencies of 3.0 to 4.5 fractures/m were used as values for the

Grouse Canyon. The CSIR joint spacing of Tunnel Bed 5 was rated based

on the joint spacings of 0.5 to 1.0 fracture/ observed in drifts at

G-Tunnel. The fracture-frequency ranges used and the ratings the authors

assigned to the CSIR joint-spacing parameter are shown in Table 15.

5.2.4 Joint Alteration

One of the parameters in the GI system is a Joint Alteration

lumber. This subsection describes how descriptions of joint alteration

were correlated with NGI joint-alteration categories to assign a numerical

rating to Jn

Fracture descriptions were provided by the USGS that included de-

scriptions of the mineral fillings along joints, based on visual exami-

nation in the field. In some cases, the minerals in the coatings or

fillings could not be identified, and a color description was given in-

stead of an identification of the minerals. In some cases, the approx-

imate thickness of the filling or coating was given. If no thickness was

provided, the'authors assumed that a "coating" was <I m in thickness and

a "filling" was probably 1 mm thick.

65

TABLE 15

CSIR RATINGS FOR JOINT SPACING FOR THU TUFF UNITS

Joint FrequencyTuff Unit (Wma) CSIR Ratinn

Topopah Spring 2.0 - 16.0 10 - 20

Calico Hills 0.5 - 1.2 20 - 25

Bullfrog 1.0 - 9.0 10 - 20

Tram 2.0 - 6.0 10 - 20

Tunnel Bed 5 0.5 - 1.0 20 - 25

Grouse Canyon 3.0 - 4.5 10 - 20

In assigning a Ja description to the units, the authors assumed

that any joint alteration reported for at least 30% of the fractures in a

given drillhole for a given unit was significant and should be considered

when assigning a rating to J . Bar graphs showing the fracture fillings

and coatings of the fractures mapped from the core are given in Appendix

B. The fracture coatings and fillings described on some of the bar graphs

sum to more than 100 because more than one mineral type or coating color

often occurred along a single fracture. There are two bar graphs for each

drillhole and unit: one for fractures inclined at less than 45- and the

other for fractures inclined at more than 45-.

For the most part, the fracture fillings in the Topopah Spring are

thin (i.e., the fracture surfaces were described as coated or discolored).

In Drillhole USW G-4, 40% of the fractures inclined at more than 450 and

60% of the fractures inclined at less than 45- were described as being

discolored. For this reason, the upper-limit J description assigneda

to the Topopah Spring was "unaltered joint walls, surface staining only."

Although silica fillings or coatings were identified, they usually occur

in combination with other soft fillings. For this reason, the upper

66

bound was not classified with the J description, "tightly healed, hard,

nonsoftening impermeable fill, i.e., quartz or epidote." On several

fractures, softening minerals were identified. In Drillhole USW G-l(a),

approximately 80% of the coatings are clay; and in Drillhole UE-25a1,

approximately 30% of the fractures with inclinations greater than 45- are

coated with either clay or calcite. Accordingly, the lower-limit descrip-

tion of Ja assigned to the Topopah Spring was "softening or low-friction

clay mineral coatings." The evidence for faulting or fracture movement

was restricted mostly to slickensides, which occur in less than 5% of the

fractures, except in Drillhole USW G-l(a). In this drillhole, 12% of the

fractures inclined at less than 450 exhibit slickensides.

Fracture fillings in the Calico Hills are also generally thin. In

Drillhole USW G-4, approximately 80% of the fractures were described as

discolored. In Drillhole USW G-1(b), only five fractures were identified,

and only two (20%) had an iron stain on the fracture surface. On this

basis, the authors assigned an upper-limit description of Ja of "unal-

tered joint walls, surface staining only," to the Calico Hills. In Drill-

hole USW G-l(a), 100% of the fractures have clay coatings; therefore, the

authors assigned a lower-limit description of Ja' "softening or low-

friction clay mineral coatings," to the Calico Hills. Slickensides occur

along approximately 15% of the fractures in the core from the Calico

Hills portion of Drillhole UE-25a#l.

Many fracture fillings in the Bullfrog are thin. In Drillhole

USW G-4, approximately 40%'tf the fractures inclined at more than 45- and

100% of the fractures inclined at less than 45- were filled or coated

with silica; therefore, the-authors assigned an upper-limit description

of Ja, "tightly healed, hard, nonsoftening, impermeable filling," to

the Bullfrog. The evidence for faulting or fracture movement in the

Bullfrog includes slickensides from UE-25a#l, USW G-l(b), and USW GU-3.

In Drillhole UE-25a01, approximately 35% of the fractures inclined at

more than 45- and approximately 25% of the fractures inclined at less

than 45- exhibit slickensides. In Drillhole USW G-l(b), approximately

50% of the fractures inclined at less than 450 exhibit slickensides. In

Drillhole USW GU-3, less than 5% of the fractures contain slickensides.

67

The evidence of faulting or fracture movement reported for Drillhole

USW G-l(a) was mainly breccia or souse. Approximately 35% of the frac-

tures inclined at more than 45- and approximately 20% of the fractures

inclined at less than 450 contained breccia or gouge. Because there was

evidence of faulting (movement) in the Bullfrog in several of the drill-

holes and because most of the faulting evidence in USW G-1(a) includes

breccia or gouge, the lower bound for the Bullfrog was placed in the Ja

category "rock wall contact before shear" and a a description was

assigned of "medium or low over-consolidation, softening, clay mineral

fillings." This lower-bound category was chosen because (1) some of the

descriptions indicated that the rock walls were no longer in contact,

(2) the nfilling material indicated movement along the fracture, and

(3) the fractures with these infillings did not occur in zones or bands

as described in the next Ja category. This description for the Bull-

frog is probably conservative because so much of the faulting evidence is

restricted to slickensides, which indicates that there is rock wall

contact.

Many of the fracture fillings in the Tram unit are thin. n Drill-

hole USW G-4, approximately 95% of the fractures inclined at less than

45- were coated or filled with silica; therefore, the authors assigned an

upper-limit description of J to the Tram of "tightly healed, hard,anonsoftening, impermeable fillings." The evidence of faulting in the

Tram is scarce, except in USW G-1(a). In this drillhole, approximately

30 of the fractures inclined at less than 45 and approximately 25 of

the fractures inclined at more tan 450 contained gouge. Although there

is little faulting evident in the other drillholes, to be onservative,

the same lower bound used for the Bullfrog was used for the Tram. The

J description the authors assigned for the lower bound is "medium or

low overconsolidation, softening, clay mineral fillings" with "rock wall

contact before 10 cm shear."

The only detailed information for joint alteration in the units at

G-Tunnel comes from Drillholes U12gCB#1 and U12gCB#2 and pertains to the

Grouse Canyon. This information indicates that most (40-60%) of the

fractures are not coated and that the remainder are only coated, not

filled. From these data and from direct observation of the tunnel walls,

68

an upper-bound description of a "unaltered joint walls, surface stain-

ing only," and a lower-bound description of am "slightly altered joint

walls," were assigned to the Grouse Canyon. Based on direct observation

of the tunnel walls, the same range of Ja descriptions was assigned to

Tunnel Bed 5.

The GI J descriptions and associated ratings for J assigned to

the tuff units are summarized in Table 16.

5.2.5 Joint Roughness

One of the parameters in the GI system is Jr, Joint Roughness

Number. In the GI system, descriptions of joint roughness are related

to numerical ratings. The GI Jr depends on the planarity of the

joints. Planarity was usually reported in the fracture descriptions by

the USGS (Scott, 1983a, 1983b, and 1983c; Scott and Castellanos, 1982;

Spengler, 1982a and 1982b). The planarity descriptions are summarized in

Tables 17 through 20. Each table is divided into those fractures inclined

at greater than 450 and those inclined at less than 45-. Because nearly

vertical fractures are more numerous, the authors gave more weight to

descriptions for fractures inclined at more than 45-. Most of the nearly

vertical fractures in all the units, except those in USW G-4, are non-

planar. In USW G-4, most joints are nearly planar to slightly planar.

Also, in Drillhole USW G-4, the Calico Hills had the highest percentage

of joints that were nearly planar to slightly planar.

This planarity information was supplemented by mapping and observa-

tion of fractures in the G-Tunnel complex. The fractures in the Grouse

Canyon are generally discontinuous, and those that are continuous change

attitude within a foot or two. Although an individual fracture is usually

discontinuous, the same fracture trend may be continued by another frac-

ture within a foot of the first fracture. Fractures in Tunnel Bed 5 are

more continuous and planar than those in the Grouse Canyon.

69

TABLE 16

NGI RATINGS FOR JOINT ALTERATION Wa) IN THE TUFF UNITS -

Tuff UnituGI

Joint Alteration Description NGI a Factor

Topopah Spring

Calico Hills

Bullfrog

"Unaltered joint walls, surfacestaining only" to "softening or lowfriction clay mineral coatings"

"Unaltered joint walls, surfacestaining only" to "softening or lowfriction clay mineral coatings"

"Tightly healed, hard, nonsoftening,impermeable filling (i.e., quartz orepidote)" to "medium or low over-consolidation, softening, claymineral fillings (continuous <5 mm inthickness)"

1.0 - 4.0

1.0 - 4.0

0.75 - 8.0

Tram "Tightly healed, hard, nonsoftening,impermeable filling (i.e., quartz orepidote)" to "medium or low over-consolidation, softening, claymineral fillings (continuous <5 mm inthickness)"

0.75 - 8.0

Tunnel Bed 5

-Grouse Canyon

"Unaltered oint walls, surfacestaining only" to "slightly alteredjoint walls"

"Unaltered joint walls, surfacestaining only" to "slightly alteredjoint walls"

1.0 - 2.0

1.0 - 2.0

The information on planarity of joints and joint continuity, as wall

as previous information on the percentage of faults, was used to determine

the appropriate description for the J for each of the units.r

70

TABLE 17

FROM DRILLHOLES IN THE TOPOPAH SPRINGPLANARITY INFORHATION

PlanarityDescription

Percentage of Descriptionsfor Fractures Inclined at >45w

UE-25affl

0

USW G-1(a) USW -1(b) USW G-3

76 89 50Nonplanar

Nearly Planar orSlightly Planar

0 13 0

4

7

21

24

4

USW G-4

27

65

8

0

Planar 0 3

7So Definition 100

Percentage of Descriptionsfor Fractures Inclined at <45-

UE-25a#1

0

USW G-1(a) USW G-1(b) USW GU-3

75 50 44

USW G-4

9Nonplanar


Planar

go Definition

0 11 0

17

33

20 91

0

100

3

9

34 0

4 0

The descriptions of Jr assigned to the joints in the Topopah Spring

and Grouse Canyon units were "discontinuous" to "smooth, undulating."

These assumptions were based on the joint planarity of the Topopah Spring

(Table 17), on observations of the Grouse Canyon in the G-Tunnel complex,

and on the fact that the Topopah Spring unit exhibits compressive strengths

and numbers of fractures that are similar to those of the Grouse Canyon.

The joints in Tunnel Bed 5 and the Calico Hills were both assigned descrip-

tions for Jr of "smooth, undulating" as a lower bound and "smooth,

planar" as an upper bound. These descriptions were based on observations

of the nonwelded tuffs in the G-Tunnel complex (i.e., the fractures in

the nonwelded tuffs are more continuous than those in the Grouse Canyon)

71

TABLE 18

PLANARITY INFORMATION FROM DRILLHOLES IN THE CALICO HILLS


Percentage of Descriptionsfor Fractures Inclined at >45*

UN-250#1

0

USW G-1(a) USW G-1(b) USW GU-3

78 0 NP*Nonplanar


0 11 0

0

100

NP

NP

NP

USW G-4

6

82

12

0

Planar 0 11

0No Definition 100

Percentage of Descriptionsfor Fractures Inclined at <45-

UR-25a#1 USW G-1(a) USW G-l(b) USW GU-3 USW G-4

Nonplanar

Yearly Planar orSlightly Planar

Planar

No Definition

0 100

0 0

100

0

0

0

NP 0

NP 80

0 0

0

NP 20

100 NP 0

*NP - Not present (the zeolitized nonwelded Calico Hills Unit was notpresent). -

and on the fact that the Calico Hills and the nonwelded tuff in the

C-Tunnel complex have similar compressive strengths. The joints in the

Bullfrog and Tram units were assigned Jr descriptions of "discontinuous"

as an upper bound and "slickensided, undulating" as a lower bound. Al-

though most of the faults in the Tram were filled with gouge, and one

drillhole in the Bullfrog included several faults with gouge, the joints

in both the Bullfrog and Tram were assigned a lower bound of "slicken-

sided, undulating" because they were considered to fit in the category of

"rock wall contact before 10 cm shear."

72

TABLE 19

PLANARITY INFORMATION FROM DRILLHOLES IN THE BULLFROG


Percentage of Descriptionsfor Fractures Inclined at >45-

UE-25a#1

0

USW G-l(a) USW G-1(b) USW GU-3

100 88 84Monplanar

USW G-4

20

30Nearly Planar orSlightly Planar

0 0 0

0

12

11

4

1

Planar 0 0

0

8

No Definition 100 42

Percentage of Descriptionsfor Fractures Inclined at <450

UE-25all

0

USW G-l(a) USW G-l(b) USW GU-3

100 50 68Nonplanar


Planar

No Definition

0

0

100

0

0

0

0

0

17

14

USW -4

0

44

33

2250 1

Table 21 summarizes the KGI Jr descriptions and the-corresponding

ratings assigned to each tuff unit.

5.2.6 Condition of Joints

One of the parameters in the CSIR system is Condition of Joints. To

assign ratings to the tuff units for joint condition, the joint rough-

ness, joint filling, and compressive strength information described

previously were considered.

73

TABLE 20

PLANARITY INFORMATION FROM DRILLHOLES IN THE TRAM


Percentage of Descriptionsfor Fractures Inclined at >45-

US-25a#1 USW G-l(a) USW G-l(b) USW G-3

Nonplanar


Planar

No Definition

NA* 85 82

0

75

22NA

NA

NA

2

0

12

USW G-4

40

56

4

0

0

18

1

2

Percentage of Descriptionsfor Fractures Inclined at 450

Nonplanar


Planar

No Definition

UR-25a#1

NA

NA

NA

NA

USW G-l(a) USW G-l(b) USW GU-3

93

3

0

3

80

0

0

20

68

16

5

11

USW G-4

0

94

6

0

*NA No data available (Drillhole U25a#1 did not reach the Tram Unit).

The CSIR descriptions assigned to the fractures in the Topopah Spring

were "slightly rough surfaces, separation of less than 1 mm, hard-joint

wall rock" as a lower bound and "very rough surfaces, not continuous, no

separation, hard-joint wall rock" as an upper bound. The following

information was used to support these descriptions.

The wall rock of the joint is probably hard because the Topopah

Spring has a high compressive strength and many of the joint

walls include only surface staining.

74

TABLE 21

RGI RATINGS FOR JOINT ROUGHNESS (Jr) FOR THE TUFF UNITS

UGIJoint Rouxhness DescriptionTuff Unit - GI Rating

Topopah Spring

Calico Hills

Bullfrog

Discontinuous joints to smooth,undulating

Smooth, undulating to smooth, planar

Discontinuous joints to slickensided,undulating

4.0 - 2.0

2.0 - 1.0

4.0 - 1.5

Tram Discontinuous joints to slickensided,undulating

4.0 - 1.5

Tunnel Bed 5

Grouse Canyon

Smooth, undulating to smooth, planar

Discontinuous joints to smooth,undulating

2.0 - 1.0

4.0 - 2.0

* Little (less than 1 mm) or no material fills the fractures.

* The Grouse Canyon, a tuff with a compressive strength similar to

that of the Topopah Spring, has discontinuous joints.

* The fractures are mostly nonplanar, and few are smooth.

The CSIR descriptions assigned to the joints in the Bullfrog and Tram

were slightly rough surfaces, separation of less than 1 mm, hard-joint

wall rock" as an upper bound and "slickensided surfaces or gouge of less

than 5 mm thick or joints open 1 to 5 mm, continuous joints" as a lower

bound. The following information was used to support the upper-bound

descriptions.

* The Bullfrog and Tram units exhibit relatively high compressive

strength in comparison to that of the Tuffaceous Beds of Calico

Hills.

75

Little (less than 1 mm) or no material fills the fractures.

* The Grouse Canyon Member, a tuff with a fracture frequency

similar to that of the Topopah Spring, has joints that are

discontinuous.

* Host of the joints are nonplanar, and few are smooth.

Information used to support the lower-bound description includes the

observation that more than 30% of the fractures in one or more of the

drillholes include slickensides or gouge, and the thickness of the gouge

is less than 5 mm.

The CSIR description assigned to the joints in the Calico Hills was

"slightly rough surfaces, separation of less than 1 mm, soft-joint wall

rock." The following information was used to support this description.

* The tuff exhibits a relatively low compressive strength;

therefore, the joint wall is considered soft.

* Little (loss than 1 mm) or no material fills the fractures.

* Most of the joints are nonplanar or only slightly planar, and

few are smooth.

The CSIR description assigned as a lower bound to the joints in the

Grouse Canyon Member was "slightly rough surfaces, separation of less

than 1 mm, hard-joint wall rock" as a lower bound and "very rough

surfaces, not continuous, no separation, hard-joint wall rock" as an

upper bound. The following information supports this description.

* The wall rock of the joint was described as hard because the

Grouse Canyon has a high compressive strength and most of the

joint walls include only surface staining.

* Most of the fractures have little (less than 1 mm) or no

separation.

76

* Most of the fractures are discontinuous.

* The fractures are nonplanar and are not smooth.

A CSIR description of "slightly rough surfaces, separation of less

than 1 mm, soft-joint wall rock" was assigned to the joints in Tunnel

Bed 5. The following information supports this description.

* The wall rock of the joint was described as soft because Tunnel

Bed 5 has a low compressive strength and most of the joint walls

include only surface staining.

* The fractures have little (less than 1 mm) or no separation.

* The fractures are nonplanar or slightly planar and are not

smooth.

Table 22 summarizes the CSIR ratings for joint condition assigned to

all the tuff units.

5.2.7 Joint Orientation with Respect to Emplacement Drifts

The CSIR system is unique because it includes a parameter, Rating

Adjustment for Joint Orientation, based not only on a basic property of

the rock but also on how the structure being rated is designed.

Bieniawski gives guidelines (Table 23) for associating the relation-

ship between joint and tunnel orientations with various qualitative

descriptions. None of the conditions listed in the table provides an

exact fit with the possible orientation relationships between the joints

and drifts at Yucca Mountain and -Tunnel. This conclusion for the

Topopah Spring, Bullfrog, Tram, and Grouse Canyon is based on two assump-

tions: (1) many of the joints in the Topopah Spring, Bullfrog, and Tram,

like the joints in the Grouse Canyon, are discontinuous and (2) the joints

in the Topopah Spring, Bullfrog, and Tram, like the joints in the Grouse

Canyon, do not include one dominant joint set but two or three joint sets

of comparable frequency and persistency. It is assumed in all of the

77

TABLE 22

CSIR RATINGS FOR CONDITION OF JOINTS IN THE TUFF UNITS

Tuff UnitCSIR

Joint Condition Description CSIR Rating

20 - 25Topopah Spring "Very rough surfaces, not contin-uous, no separation, hard jointwall rock" to "slightly roughsurfaces, separation <1 mm, hardjoint wall rock"

Calico Hills "Slightly rough surfaces, separation<1 mm, soft joint wall rock"

12

Bullfrog "Very rough surfaces, not contin-uous, no separation, hard jointwall rock" to "slickensided surfacesor gouge <5 mm thick"

6 - 25

6 - 25Tram "Very rough surfaces, not contin-uous, no separation, hard jointwall rock" to slickensided surfacesor gouge <5 mm thick"

Tunnel Bed 5

Grouse Canyon

"Slightly rough surfaces, separation<1 m, soft joint wall rock"

"Very rough surfaces, not contin-uous, no separation, hard jointwall rock" to "slightly roughsurfaces, separation <1 mm,hard joint wall rock"

12

20 - 25

conditions listed in Table 23 that there is one dominant joint set. Two

or three joint sets of comparable frequency and persistency make it more

difficult to engineer the stability of the drift as a function of its

orientation. In some places in a drift, the blocks created by the many

joint sets could key other blocks and prevent movement of rock, and, in

other places, the joints might intersect and free a block of rock to

slide into the drift. The latter possibility is not as likely if the

joints are discontinuous.

78

TABLE 23

THE EFFECT OF JOINT STRIKE-AND-DIP ORIENTATIONS IN TUNUELING

Strike Perpendicular to Tunnel AxisStrike Parallel

Drive with Dip Drive Atainst Dip to Tunnel Axis

Dip0' - 200

Dip 45- Dip 20- Dip 450 Dip 20- Dip 45- Dip 200 Irrespective-90- -45- -900 -45- -90- -450 of Strike

Very Veryfavorable Favorable Fair Unfavorable unfavorable Fair Unfavorable

Source: Bieniawski (1976, p. 102).

The limited experience at G-Tunnel regarding the orientation of

drifts to joints in the Grouse Canyon does not provide much useful

guidance on how to favorably orient the repository drifts. All of the

drifts in the Grouse Canyon are driven at an angle to the joints.

Because most of the joints are nearly vertical, there are only two main

types of drift orientations: those parallel to a joint set and those at

an angle to all joint sets.

To determine a value for the Rating Adjustment for Joint Orientation,

one basic assumption was made in all cases; that is, the joints in the

range of 45 to 90 are so numerous in comparison with the remainder of

the joints that only these joints need be considered when assigning a

description to the relationship between the joint and drift orientations.

Upper- and lower-bound descriptions were assigned to the Topopah Spring,

Bullfrog, Tram, and Grouse Canyon using this assumption. An upper-bound

description of "very favorable" was assigned to the Topopah Spring, Bull-

frog, Tram, and Grouse Canyon units, assuming that the following condi-

tions would correspond to the conditions for a "very favorable" drift

orientation presented in Table 23.

Discontinuous joints are present that are less likely to create

blocks of rock that are free to slide into the drift.

79

* Most of the joints that intersect create blocks that key other

blocks to prevent movement of rock into the drift.

* The orientation of the drift is not parallel to any of the joint

sets.

A lower-bound description of "very unfavorable" was assigned to the

Topopah Spring, Bullfrog, Tram, and Grouse Canyon units, based on the

assumption that the following conditions correspond to the conditions for

a "very unfavorable" drift orientation when there is only one joint set.

* There are more continuous joints than discontinuous joints, and

thus it is more likely that the joints will intersect to form

free blocks of rock.

* Host of the joints intersect to provide blocks of rock that do

not key other blocks, and thus the blocks of rock are free to

move into the drift.

* The drift is parallel in orientation to one of the joint sets.

Neither the Calico Hills unit nor the Tunnel Bed 5 unit exactly fits

any guidelines given in Table 23. Although the fractures in Tunnel Bed

appear to be more continuous than those in the Grouse Canyon, the frac-

tures in the two units share the characteristic of having more than one

set of fractures and of having inclinations mainly of 45 to 900.

At G-Tunnel, drifts in Tunnel Bed 5 have been driven at many differ-

-ent orientations. This experience does not indicate any difference in

the favorability of the different drift orientations, possibly because

the joints are widely spaced and have different orientations. Host

drifts at G-Tunnel are 3.6 to 4.6 m (12 to 15 ft) wide and 3.0 to 3.6 m

(10 to 12 ft) high. At this drift size, because the fractures are few

and have varying orientation, there does not appear to be a strong

dependency of the favorability of the drift orientation on the joint

orientation.

80

The Calico Hills and Tunnel Bed 5 units were assigned the same de-

scription ranges for the Rating Adjustment for Joint Orientations as

those that were assigned for the remainder of the units. The Calico

Hills and Tunnel Bed 5 units were assigned an upper-bound description of

"very favorable," based on two different logic paths. Although the

emplacement drifts will be larger* than the drifts at -Tunnel, the

drifts may still be small enough that the favorability of the drift

orientation will not depend strongly on the joint orientation. For such

drifts, any orientation would essentially be "very favorable." If the

joints are numerous enough that a favorable drift orientation is dependent

on the joint orientation, it is assumed that a "very favorable" condition

would exist if the drifts are oriented nonparallel to all joint sets.

The Calico Hills and Tunnel Bed 5 units were assigned a lower-bound

description of "very unfavorable" based on two assumptions.

* The joints are numerous enough that a favorable drift orienta-

tion is dependent on the joint orientations.

* The drifts are oriented parallel to one of the joint sets.

Because the ratings for this category are the same for all the units,

"very favorable" ( points) to "very unfavorable" (-12 points), no

"rating" table is provided that summarizes the results. The summary

discussions (Sections 6, 7, and 8) at the end of this report treat this

parameter differently from the remainder of the parameters in the CSIR

system. The summary discussions present a range of results that assumes

a "very favorable" drift orientation as well as a range of results that

encompasses all possible conditions. Both ranges are presented because

drift orientation can be controlled, and it is assumed that, if possible,

the drifts will be oriented favorably with respect to the joints.

* Two different designs are currently being considered for emplacementdrifts at Yucca ountain: a drift with a height of 6.7 m (22 ft) and awidth of 4.9 m (16 ft) for vertical emplacement of waste and a driftwith a height of 4.0 m (13 ft) and a width of 6.1 m (20 ft) forhorizontal emplacement of waste (Hill, 1985).

81

5.3 Groundwater-Related Properties

The NGI and CSIR systems each have one parameter to rate ground-

water. The NGI parameter is called the Joint Water Reduction Factor

(Jw) and the CSIR parameter is called Groundwater. The NGI system

provides two main ways to rate the groundwater: descriptions of the

general groundwater conditions and approximate water pressure. The CSIR

system provides several ways to rate groundwater. The groundwater param-

eter can be assigned a value based either on the inflow per 10 a (33 ft)

of drift length, on the ratio of the joint water pressure to the major

principal stress, or on a description of the general groundwater condi-

tions.

The vertical flux in the matrix of the unsaturated Topopah Spring has

been estimated to range from 10 to 0.2 mm/yr (ontazer and Wilson,

1984). To determine the inflow per 10 m (33 ft) of drift length, the

horizontal dimension of a waste-emplacement drift must be used. Two dif-

ferent designs for emplacement drifts are currently being considered: a

drift with a height of 6.7 m (22 ft) and a width of 4.9 a (16 ft) for

vertical emplacement of waste and a drift with a height of 4.0 m (13 ft)

and a width of 6.1 m (20 ft) for horizontal emplacement of waste (Hill,

1985).

The maximum water inflow per 10 m (33 ft) for the horizontal-

emplacement design can be determined by assuming that the vertical flux-7 2

is 0.2 m/yr (3.8 x 10 L/m /min). The maximum water-inflow rate

per 10 m (33 t) of drift would be 2.3 x 10 L/min. This water-inflow

rate was used to select a CSIR groundwater rating of 10 for the Topopah

Spring. It has been estimated that the groundwater flux in the Calico

Hills is limited to 0.006 myr in the downward direction (ontazer and

Wilson, 1984, . 52). If the same dimensions were used for emplacement

drifts in the Calico Hills, the maximum water-inflow rate for the Calico

Hills would be even less than that for the Topopah Spring. Based on this

reasoning, a CSIR groundwater rating of 10 was also assigned to the Calico

Hills.

82

Because both of these tuff units are unsaturated, the water pressure

in the joints is nearly atmospheric, which is a negligible amount for the

purposes of this report, particularly when the water pressure in the

joints is compared with the much greater overburden stress. Because of

the slight water flow into an emplacement drift and the negligible water

pressure in the joints, an GI J rating of 1.0 was assigned to both

the Topopah Spring and the Calico Hills. The range of groundwater flow

values calculated using the range of percolation rates and proposed drift

designs is reported in Table 24. Because conditions in the G-Tunnel

complex are essentially dry, a CSIR groundwater rating of 10 and a GI

Jw rating of 1.0 were also assigned to the Grouse Canyon and Tunnel

Be 5.

Three properties are needed to calculate the groundwater inflow per

10-m (33-ft) length of drift for the saturated units (the Bullfrog and

Tram): the hydraulic gradient, the hydraulic conductivity, and the

emplacement-drift dimensions. From contours of the groundwater table

(Robison, 1984, p. 4), the hydraulic gradient within the potential

surface boundary of the underground facility appears to have a local high

of 0.07 m/m and an average of 0.009 mm.

Hydraulic conductivities reported from well tests (USW H-1, J-13,

and UE-25bfflH) in the Bullfrog indicate a range of 7.0 x 10 to 1.1 m/day

(Rush et al., 1984, p. 40; Barr, 1985, pp. 5 and 22; Lahoud et al., 1984,

p. 39; Thordarson, 1983, p. 24). The high hydraulic conductivity was

found in UE-25btlH in a portion of the Bullfrog Member that contained a

fault zone. Water production was attributed to this fault (Lahoud et al.,

1984, p. 31). Therefore, this value may be representative of a local con-

dition. The next highest hydraulic conductivity reported was 1.6 x 10r m/day

(Thordarson, 1983, p. 24). Hydraulic conductivities reported from well

tests (USW H-1, USW H-3, J-13, and UE-25b#lH) in the Tram indicate a range

of 6.0 x 10 to 2 x 10 i m/day (Rush et al., 1984, p. 40; Barr, 1985,

pp. 5 and 22; Lahoud et al., 1984, p. 39; Thordarson, 1983, p. 24;

Thordarson et al., 1985, p. 33).

83

TABLE 24

CSIR AND GI RATINGS OF GROUNDWATER FOR THE TUFF UNITS

Tuff Unit

Topopah Spring

Calico Hills

Groundwater Inflow per10 m (33 ft) of Drift

(L/min)

9.3 x 10-13 to2.3 x 10-6

5.6 x 10-8 to7.0 x 10-8

Ratio ofJoint Water

Pressure to MajorPrincipal Stress

WaterPressure

ePa) CSIR RatingUGI

Jw Description

Negligible

Negligible

NGI Rating

Negligible

Negligible

10

10

"Dry excavationor minor inflow,i.e.. <5 L/minlocally"

1.0

1.0

Bul lfrog 4.4 x 10-8 to3.2 or 0.05

3.8 x 10-8 to0.06

0.1

0.15

1.7

3.0

7

7

..Medium inflowor pressure,occasional out-wash of jointfillings"

to"large inflowor high pressurein competentrock withfilled joints"

0.66 - 0.5

0.66 - 0.5Tram

Tunnel Bed 5 * * 10

10

"Dry excavationsor minor inflowi.e., 5 L/minlocally"

1.0

Grouse Canyon * * * 1.0

*No measurements were available to permit categorization of the groundwater parameters.were chosen on the basis of observation of drifts.

Ratings for groundwater parameters

The maximum groundwater flux in the Bullfrog would be 0.053 L/m /min

if a hydraulic conductivity of 1.1 /day were used and 7.8 x 10 L/m2/min

if a hydraulic conductivity of 1.6 x 10 2 were used. The maximum ground-2

water flow in the Tram is 0.001 L/m min. For the Bullfrog, the maximum

water inflow per 10-m (33-ft) length of a drift with a width of 6.1 m

(20 ft) would be 3.2 L/min (for a hydraulic conductivity of 1.1 m/day) or

0.05 L/min (for a hydraulic conductivity of 1.6 x 10 2 m/day), and for the

Tram it would be 0.06 L/min. The minimum groundwater flux in the Bullfrog

would be 4.4 x 10 8 L/m2/min, and in the Tram it would be 3.8 x 10 8

L/m min. For the Bullfrog, the minimum water inflow per 10-m (33-ft)

length of a drift with a width of 4.9 m (16 ft) would be 2.2 x 10 6-6

L/min, and for the Tram it would be 1.8 x 10 L/min.

Assuming that a repository in the Bullfrog and Tram units is located

about 175 m (574 ft) and 310 m (1017 ft), respectively, below the water

table (Johnstone et al., 1984, p. 3), the water pressure in the joints

would be of the order of 1.7 Pa and 3 Pa, respectively. Thus, the

ratio of the joint water pressure to the overburden stress (from Table 7)

is approximately 0.1 in the Bullfrog unit and 0.15 in the Tram. These

estimates, together with the groundwater inflow of 3.2 L/min for the

Bullfrog and 0.06 L/min for the Tram, form the basis for selecting a CSIR

groundwater rating of 7 for both of the units.

For the GI system, water pressures of 1.7 and 3 Pa (17 and 30

kg/cm ) in the Bullfrog and Tram, respectively, require an assignment

of a Jw of 0.1 for both units. A water flow of less than 5 L/min

locally into a drift is associated with a w value of 1.0. Based on

the above calculations of water-inflow rates and water pressure, together

with the qualitative descriptions of various physical conditions asso-

ciated with the various values of the GI parameter Jw, a rating range

of 0.66 to 0.5 was selected for Jw for the Bullfrog and Tram.

The values for rate of water inflow, ratio of joint water pressure to

principal stress, water pressure, and the assigned CSIR and GI ratings

are summarized in Table 24. The qualitative descriptions corresponding

to the GI ratings are also listed in this table.

85-86

6.0 FINAL RESULTS OF THE ROCK-MASS CLASSIFICATION OF THE TUFF UNITS

In the preceding sections, the properties, characteristics, and

conditions of the tuff units have been discussed and evaluated so that

values can be assigned to the rock-mass-classification parameters used in

the CSIR and GI systems. These values are summarized in Table 25 for

the CSIR system and in Table 26 for the GI system. The RHR and Q values

for each tuff unit are simple arithmetic combinations of the values as-

signed to each parameter. The final range of RR values for the tuff

units is plotted in Figure 21. The final range of Q values is plotted in

Figure 22. These plots indicate that there is a lot of overlap among the

units in the final RHR and Q values. The RR and Q values can be corre-

lated with the qualitative descriptions of rock-mass quality for each

system, using Tables 2 and 3, respectively. These qualitative descrip-

tions are given in Tables 25 and 26 and are summarized in Table 27. On

the basis of the plots and qualitative descriptions, the tuff units are

ranked in three groups; the first group represents the highest rock-mass

quality on a relative basis:

Group 1: Topopah Spring and Grouse Canyon

Group 2: Calico Hills and Tunnel Bed 5

Group 3: Bullfrog and Tram.

This grouping is included in Table 27.

Keeping in mind the above groupings and examining Figures 21 and 22,

there are five points to note.

* Although the ranges of Q and RMR values overlap, the rock-mass

quality of the first group is slightly better than that of the

second group. The upper-bound value for RR is higher for Group

1, and the lower-bound value for Q is higher for Group 1.

* The Q values for the first group overlap slightly with those for

the third group, but the overall range of Q is significantly

better for the first group than for the third group.

87

Parameter

Strength of Intact Tuff

Drill Core Quality RQD)

Spacing of Joints

Condition of Joints

coco Groundwater

Rating Adjustment forJoint Orientations

TopopNSpr ing

8 to

10 to 2

20 to 2

0 to -

TABLE 25

FINAL CSIR CLASSIFICATION RATINGS FOR THE TUFF UNITS

Tuff Unit

ah CalicoI Hills Bullfrog Tram

12 2 to 4 4 to 7

17 17 to 20 13 to 20 17 to 21

!O 20 to 25 10 to 20 10 to 21

25 12 6 to 25 6 to 2!

LO 10 7

-12 0 to -12 0 to -12 0 to-:

I

7

L2

Tunnel Bed 5

1 to 2

20

20 to 25

12

10

0 to -12

GrouseCanyon

7 to 12

8 to 13

10 to 20

20 to 25

10

0 to -12

Rock Mass Rating (RHR) 48 to 84 49 to 71 28 to 79 35 to 79 51 to 69 43 to 80(60 to 84) (61 to 71) (40 to 79) (47 to 79) (63 to 69) (55 to 80)

Rock Mass Class Number I to III II to III II to IV II to IV II to III II to III(I to III) (II) (II to III) (II to III) (II) (II to III)

Rock Mass Description Very good Good to Good to poor Good to Good to Good toto fair fair rock rock (Good poor rock fair rock fair rockrock (Very (Good rock) to fair rock) (Good to (Good rock) (Good togood to fair fair rock) fair rock)rock)

Note: Both values of the range in parentheses are based on the assumption that the drifts can be oriented very favorably'with respect to the joints.

TABLE 26

FINAL NGI CLASSIFICATION RATINGS FOR THE TUFF UNITS

Tuff Unit

Topopah CalicoSpring Hills Bullfrog Tram

-

Parameter i Tunnel Bed 5GrouseCanyon

Rock Quality Designation

(RQD)

80 - 35 99 - 85 99 - 64 96 - 78 93 51 - 37I,.

Joint Set Number

(Jn)

Joint Roughness Number

(Jr)

t

Joint Alteration Number

(Ja)

Joint Water ReductionNumber (w)

Stress Reduction Factor

(SRF)

6.0 -

4.0 -

1.0 -

12.0

2.0

4.0

0.5

2.0

1.0

- 10.0

- 1.0

- 4.0

6.0 - 12.0

4.0 - 1.5

0.75 - 8.0

0.66 - 0.5

8.7 - 11.4

6.0 - 12.0

4.0 - 1.5

0.75 - 8.0

0.66 - 0.5

6.1 - 8.9

0.5

2.0

1.0

- 10.0

- 1.0

- 2.0

1.0

- 19.0

6.0 - 12.0

4.0 - 2.0

1.0 - 2.0

1.0

1.0

1.0 1.0

1.0 9.2 - 10.9 8.0

RDXJr JwQ x SRF 53.3 - 1.46 43.0 - 0.19 6.7 - 0.04 9.2 - 0.07 46.5 - 0.24 34.0 - 3.08

Rock Mass Quality Very good Very good Fair to Fair to Very good to Good toto poor rock to very poor extremely extremely very poor poor rock

rock poor rock poor rock rock

II I I I I I I I I

TOPOPAHSPRING

_L I" m -0 -

-I I

GROUSECANYON

CALICOHILLS

I I - II~~~~~~~~~~~~~~I I

I-b -__ l I

TUNNELBED 5 I- - -- - -l

C

_IBULLFROG a-M-. - -- -

I I

TRAMI _ _

I I

I I I I I I I I

0 10 20 30 40 s0 60 70 80 90 100

Portion of overall rangethat can be eliminated Ifthe drifts can be oriented"very favorably" withrespect to the oints

ROCK MASS RATING

Figure 21. Plot of the Final CSIR Classification Ratings for the Tuff Units

'I,

4

I I I

TOPOPAHSPRING

GROUSECANYON

CALICOHILLS

TUNNELBED5

BULLFROG

TRAM

a a9 a

I

a

II

I

I ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~i

l l l

0.01 0.10 1.00 10.00 100.00

ROCK MASS QUALITY

Figure 22. Plot of the Final NGI Classification Ratings for the Tuff Units

TABLE 27

SUMMARY OF QUALITATIVE DESCRIPTIONS OF THEROCK-MASS CLASSIFICATION OF THE TUFF UNITS

CSIRDescription

NGIDescriPtionGroup Tuff Unit

Topopah Sprint

Grouse Canyon

Very good tofair rock(Very good tofair rock)*

Good tofair rock(Good tofair rock)

Very good topoor rock

Good topoor rock

1

Calico Hills Good to Very good tofair rock very poor(Good rock) rock

2Tunnel Bed 5 Good to Very good to

fair rock very poor(Good rock) rock

Bullfrog Good topoor rock(Good tofair rock)

Good topoor rock(Good tofair rock)

Fair toextremelypoor rock

Fair toextremelypoor rock

3Tram

*The CSIR descriptions in parentheses are based on the assumption thatthe drifts can be oriented "very favorably" with respect to the joints.

92

* The tuff units in each group have similar rock-mass qualities.

* The range of expected rock quality in Group 2 is less in the

CSIR system than that in the UGI system.

* Also in Groups 2 and 3, the CSIR system tends to indicate com-

paratively better rock quality than the GI system at the lower

end of the range. Although not immediately apparent, the con-

siderable range in expected rock quality according to the GI

system is principally attributable to the large variation in the

ratio of the Joint Roughness Number to the Joint Alteration

Number (J r/IJ ) for Group 3 and to the ratio of RQD to the

Joint Set Number (RQD/Jn) for Group 2.

93-94

7.0 DRIFT SUPPORT REQUIREHENTS

Using the rock-mass-classification results given in the preceding

section, it is possible to estimate the maximum widths of unsupported

roof spans, stand-up times* of unsupported roof spans of specified

widths, and support requirements for the drifts. The ratings for the

case histories on which the CSIR and UGI classification systems are based

have been correlated with these indicators for support requirements.

Using the CSIR system, Bieniawski (1976) has correlated RMR with the

stand-up time of an active unsupported roof span of a drift. The corre-

lation is based on observations of many underground tunnels and rooms of

varying dimensions under a variety of rock and groundwater conditions.

The rock types on which the CSIR system is based are principally of an

intrusive igneous or metamorphic nature. Assuming an unsupported roof

span of 6.1 m (20 ft), the stand-up times for each of the 6 tuff units

may be estimated on the basis of the RR. As given in Table 28, the

estimated stand-up time may vary from zero to a few days as a minimum,

and from 3 or 4 mo to about 3.5 yr as a maximum. The more limited range

(in parentheses) is based on the assumption that the drifts can be engi-

neered to be "very favorably" oriented with respect to the joints. For

this assumption, the minimum stand-up time varies from no days to about a

month.

For the smaller unsupported roof span of 4.6 m (15 ft) at G-Tunnel,

the stand-up times would range from 1.3 to 580 days for the Grouse Canyon

and from 5.8 to 124 days for Tunnel Bed 5. Short sections of drifts in

the Grouse Canyon and Tunnel Bed 5 have stood unsupported without roof

collapse for periods of a week or so after construction before rock bolts

and wire mesh were installed as standard safety practice. This exper-

ience indicates that the stand-up times at the lower end of the scale are

conservative for the Grouse Canyon and Tunnel Bed 5.

*Stand-up time is essentially the interval of time between the construction ofan underground opening and the collapse of that opening's roof in the absenceof artificial support.

95

TABLE 28

ESTIHATES OF UNSUPPORTED ROOF-SPAY WIDTH AND STAND-UP TIHEBASED ON THE ROCK-HASS CLASSIFICATION OF THE TUFF UNITS

CSIR SystemStand-Up Time (Days forUnsupported Roof Span

of 6.1 m)

9GI System

Unsupported Roof Spanor Room Height )Group Tuff Unit

Topopah Spring

Grouse Canyon1

3 - 930(21 - 930)*

1 - 495(8 - 495)

2.3 - 9.8

3.1 - 8.2

Calico Hills 4 - 117 1.0 - 9.0(26 - 117)

2Tunnel Bed 5 4 - 83 1.1 - 9.3

(35 - 83)

Bullfrog

3

O - 417(O - 417)

O - 417(2 - 417)

0.6 - 4.3

0.7 - 4.9Tram

*Both values of the range in parentheses for stand-up times are based onthe assumption that the drifts can be oriented "very favorably" withrespect to the joints.

To relate the Q values in the VG! system to the performance and

support requirements of underground tunnels and rooms, Barton et al.

(1974a, pp. 213-214) defined the equivalent dimension" of the excavation.

This dimension is obtained by dividing the span width, room diameter, or

wall height of the excavation by a quantity known as the "excavation

support ratio" (SR). The SR is roughly analogous to the inverse of the

factor of safety used in the design of rock slopes, and its numerical

value is related to the use for which the excavation is intended and the

extent to which some degree of rock instability is acceptable. Although

96

the ESR ranges from 0.8 to 5, a value of 1 has been chosen here as

appropriate for repository drifts. A value of 1 corresponds to the

excavation category of "power stations, major road and railway tunnels,

civil defense chambers, portals, intersections." Based on many case

histories, including that of a large cavern 24 by 43 by 37 m (79 by 141

by 121 ft) at a depth of 400 m (1312 ft) in "low-strength" tuff at NTS,

Barton et al. (1974b, Appendix) correlated the equivalent dimension of

underground excavations to the Rock Mass Quality, Q. The following

equation from Barton et al. (1974a) was used to determine the range of

maximum unsupported roof span in each of the six tuff units (Table 28).

D = 2Q0 4 (8)

where

Det equivalent dimension (because ESR is equivalent to the

unsupported roof span) and

Q Rock Mass Quality.

In Groups 1 and 2, the maximum unsupported roof span is of the order of 8

to 10 m (26 to 33 ft), and the minimum is of the order of 1 to 3 m (3 to

10 ft). In the Bullfrog and Tram units (Group 3), the maximums and mini-

mums are about 4 to 5 m (13 to 16 ft) and less than 1 m (3 ft), respec-

tively.

Barton et al. (1974a, pp. 210-229) also made a correlation between

the rock support used, the equivalent dimension of the underground exca-

vations, and the Rock Mass Quality, Q. These correlations can be used to

indicate the amount of support that was used for another rock unit with a

similar rating within a range of equivalent dimensions. The use of the

drift width for horizontal emplacement of radioactive waste [6.1 m (20

ft) and the assumption of an ESR of 1.0 to estimate the support that

might be needed in the various tuff units is continued in this report.

The tuff units are discussed as they were grouped in Table 27 because the

tuff units in each group have the same limits on support requirements.

97

If the high Q values for the units in Group 1 (the Topopah Spring and

Grouse Canyon) are representative of those units, indications are that no

support will be needed. If the low Q values are representative, indica-

tions are that untensioned, grouted rock bolts on a 1-m (3-ft) spacing

with chain-link mesh and shotcrete may suffice. For this particular NGI

support category, heavy rock bursting may occur, necessitating tensioned

rock bolts with enlarged bearing plates on a spacing of 0.8 to 1 a (2.6

to 3 ft).

If the high Q values for the units in Group 2 (the Calico Hills and

Tunnel Bed 5) are representative of those units, indications are that no

support will be needed. If the low Q values are representative, indica-

tions are that the support needed may range from only mesh-reinforced

shotcrete to tensioned, grouted rock bolts on a 1-m (3-ft) spacing with

mesh-reinforced shotcrete to steel-reinforced cast-concrete arches that

are 20 to 50 cm (7.9 to 19.7 in.) thick with tensioned, grouted bolts on

a 1-m (3-ft) spacing. Mesh-reinforced shotcrete and tensioned, grouted

rock bolts were used in rock in which no swelling clay or squeezing rock

was present. Steel-reinforced cast-concrete arches were used in ground

with and without swelling clay or squeezing rock. In the cases of

swelling clay or squeezing rock, the tensioned, grouted bolts suggested

for use with the cast-concrete arches were often used as temporary

support until the cast-concrete arches could be formed.

If the high Q values for the units in Group 3 (the Tram and Bullfrog)

are representative of those units, indications are that the support re-

quired might range from spot bolting using untensioned, grouted bolts or

2 to 3 cm (0.8 to 1.2 in.) of shotcrete to untensioned, grouted bolts on

a 1- to 1.5-m (3- to 5-ft) spacing with 2 to 3 cm (0.8 to 1.2 in.) of

shotcrete. For these high Q values, heavy rock bursting may occur,

necessitating tensioned rock bolts with enlarged bearing plates on a

spacing of 0.8 to 1 a (2.6 to 3 ft). If the low Q values for the units

in Group 3 are representative, indications are that the support required

could range from tensioned, grouted bolts on a 1- (3-ft) spacing with

2.5 to 5 cm (1 to 2 in.) of shotcrete to 7.5 to 15 cm (3 to 6 in.) of

98

mesh-reinforced shoterete. The first type of upport is for rock in which

there is no swelling clay or squeezing rock. The second type of support

is temporary support for rock in which there is swelling clay or squeezing

rock. "Heavy rigid support is generally used as permanent support"

(Barton et al., 974a). The support recommendations for the low Q values

for the units in Group 3 are not based on case histories because too few

case histories were available. Instead, the support recommendations are

based on the recommendations of Barton et al. (1974a).

Experience with tunnel excavation and stability in the G-Tunnel com-

plex is the only current means of verifying the estimated stand-up times

and unsupported roof spans given in Table 28. Figure 23 is a plan view

of the VDH#5 and VDH#6 intersection in Tunnel Bed 5 in the G-Tunnel com-

plex. This area, at a depth of about 433 m (1420 ft), has a relatively

high extraction ratio with roof spans of the order of 4 to 10 m (13 to

33 ft) and a narrow pillar of 1 to 5 m (3 to 16 ft). The area was

excavated about 6 to 7 yr ago, and Figure 24 is a photograph of the.

pillar in 1983. The roofs of the entries and the pillar were rockbolted

on 1.2-m (4-ft) centers, and wire mesh was installed within a few days

after construction. The photograph indicates that the nonwelded tuff has

; suffered essentially no loss of integrity, as would be evidenced by

spelling or slabbing. Furthermore, the condition of the roof indicates

no loss of load-bearing capacity, as would be indicated by roof sag and

fractures along the springline. These observations imply that the

smaller values of stand-up time and unsupported roof span in Table 28, as

well as the more extensive support requirements, are conservative.

99

f

X-CUT #4

0

SCALE 0

5 IOm. .

I I I

10 20 30 ft

b0-

Figure 23. Plan View of the Intersection of VDH#5 and VDH#6 in TunnelBed 5 in the G-Tunnel Complex

100

Figure 24. Photograph of the Pillar at the Intersection of VDH#5 andVDH#6 in Tunnel Bed S in the G-Tunnel Complex

101-102

8.0 APPLICABILITY OF THE CSIR AND GI ROCK-HASS-CLASSIFICATIOKSYSTEMS TO TUFF UNITS AT YUCCA MOUNTAIN

Several concerns must be addressed when applying the CSIR and GI

classification systems to the tuff units at Yucca Mountain. Below, four

concerns are first listed in question format and are then addressed by a

short essay.

1. Does tuff have unique qualities (qualities unlike those of the rocks

whose case histories were used to develop the CSIR and GI classifi-

cation systems) that need to be considered?

One of the more important functions of the rock-mass-classification

ratings is to provide a link between the rock characteristics and the

support needed to maintain a stable opening. Existing tunnels in

tuff indicate that there is no noticeable discrepancy in the link

between the rock-mass-quality rating and the predicted support

requirements.

Barton et al. (1974a, p. 205; 1974b, p. 64) used two case histories

of excavations in tuff to help develop the GI classification system.

The GI rating and the support used followed the trend of ratings and

support used in tunnels of other types of rock. The existing tunnels

in tuff rated in this report also indicate that the suggested support,

based on ratings from both the GI and CSIR classification systems

(although conservative on the low end), compares well with the

support being used in the tunnels. It appears that the CSIR and GI

systems can provide reasonable preliminary estimates of the support

needed.

2. The CSIR and EGI classification systems are generally regarded as

applicable to excavation of single tunnels. Are these classification

systems applicable to a repository for the disposal of radioactive

waste, which will contain a series of tunnels?

103

t

In this report, nonwelded and welded tuffs from G-Tunnel are rated,

and support needs are predicted, based on the ratings. The predicted

support needs agree well with what is currently in use in these rock

units in G-Tunnel. Because G-Tunnel is not a single tunnel but a

complex of tunnels, it appears that the CSIR and NGI classification

systems can provide a reasonable first approximation of support needs

when rating rock units that are to contain a series of tunnels.

This question will not be an issue if the horizontal emplacement

method is chosen. In this case, the drifts will be so far apart they

will act as single tunnels.

3. The CSIR classification system does not include a stress factor. How

does this lack affect the classification of the tuff units at Yucca

Mountain and G-Tunnel?

Bieniawski (1976, p. 98) published the following equation to correlate

the CSIR ratings with the Q ratings:

R1R 9*1nQ + 44. (9)

This equation was used to compare the rating values obtained from the

two systems (Table 29). The correlation between the GI ratings and

CSIR values is a little better for the high end of the range for the

less-stressed, shallow-rock units (the Topopah Spring, Calico Hills,

Grouse Canyon, and Tunnel Bed 5) than it is for the more highly

stressed deep-rock units (the Bullfrog and Tram), but the lack of a

stress factor does not appear to be the cause of the poorer correla-

tion for the more highly stressed rock units. The wide variation and

the great influence of the NGI ratios, Jr/Ja and RQD/Jn, appear

to be the major cause of this poorer correlation.

104

TABLE 29

CONPARISON OF CSIR AND GI RATINGS

Tuff UnitCSIR Rating Using

Equation 9CSIR Rating

Topopah Spring

Calico Hills

Bullfrog

48 - 84(60 - 84)*

49 - 71(61 - 71)

47 - 80

29 - 78

28 - 79(40 - 79)

15 - 61

Tram 35 - 79(47 - 79)

20 - 64

Tunnel Bed 5 51 - 69(63 - 69)

31 - 79

Grouse Canyon 43 - 80(55 - 80)

54 - 76

*Both values of the range in parentheses are based on thethe drifts can be oriented "very favorably" with respect

assumption thatto the joints.

In this report, lack of-a-stress factor in the CSIR system does not

appear to cause wide discrepancies in the ratings predicted by the

CSIR and uGI systems, although most of the case histories used to

develop the CSIR system were for shallow excavations (less than

1000 ft in depth) and in situ stress is not a factor in the CSIR

system. Although it was expected that the lack of a stress factor

would have a greater effect on the final ratings, it may be that the

large variation in fracture properties used in rating the tuff units

is masking the effect of stress.

105

4. Neither the CSIR nor the GI classification system has a factor that

accounts for the added thermal stress resulting from heat produced by

radioactive waste. How would this added stress influence the

rock-mass-classification ratings?

Rock stresses have been predicted after excavation, as well as after

waste emplacement, using thermomechanical elastic/plastic stress-

analysis computer codes containing ubiquitous vertical joints

(Johnstone et al., 1984; Branstetter, 1984).

There are also limited results of the effects of heat-induced

stresses on tuff from in situ tests in the Grouse Canyon at -Tunnel.

A heater was emplaced vertically in a borehole and the rock heated to

approximately 300-C. The borehole did not slough or show any notice-

able degradation as a result of this test (Zimmerman, 1985).

The results of computer modeling of waste emplacement indicate that

the additional thermal stresses may reduce the rock-mass ratings and

that additional rock support may be needed. However, these results,

together with the in situ test results, indicate that the rock-mass-

classification ratings will probably not change significantly. This

conclusion must be qualified because the thermal stresses are depend-

ent on many things, including rock properties, waste-emplacement

design, and areal-power density. If the use of the NGI and CSIR

classification systems is continued, the possible effect of the added

thermal stresses on the rock-mass-classification system should be

reevaluated using the current information on rock properties,

waste-emplacement design, and areal-power density.

106

APPENDIX A

PLOTS OF FRACTURE FREQUENCY AS A FUNCTION OFDRIFT INCLINATION FOR THE TUFF UNITS AT YUCCA MOUNTAIN

107-108

. V

aCs,

Z-~ a.

E~i

a: ar!

0.0 10.0 20.0 30.0 40.0 50. 60.0 70.0 80.0 90.0DRIFT INCLINATION (Degrees)

(a) Topopah Spring

q_-sN

,

oqDa

t;

qC

USW G-4 UE-25a#1

.....\ ........... .

USW G(a)

.............. ............

- ~~USW M11b) '- -- -.................... ,, -

0.0 l0.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0DRIFT INCLINATION (Degrees)

(b) Calico Hills

Figure A-1. Plot of Fracture Frequency as a Function of Drift Inclination andDrillhole for the Fractures Without Sliekensides in the TopopahSpring and Calico Hills (Derived from Scott 1983a, 1983b, 1983cand Spengler 1982b, 1982c.)

0

V

-

* C

3) M.

Ct

o

0

rd

I I I I I I~~~~~~~~~~~~~

-~~~~~~~~~~S U-3

USW -4\

UE-25a#1 USW G-1(b) USW G-1()

-------------- - - - _ _

0.0 10.0 20.0 30.0 40.0 50.0 B0.0

DRIFT INCLINATION (Degrees)70.0 80.0 90.0

(c) Bullfrog

o,qc5-

l

U0 *-1

.:

C

c:ao

q

USW C-3

USWN G-4

.................. .... '

* .,

USW G--I(a)

USlW G-1(b) - .

II , . I . I I

0.0 10.0 20.0 30.0 40.0 50.0 60.0DRIFT INCLINATION (Degrees)

70.0 80.0 90.0

(d) Tram

Figure A-1 (concluded). Pldt of Fracture Frequency as a Function of DriftInclination and Drillhole for the Fractures WithoutSlickensides in the Bullfrog and Tram (Derived fromScott 1983a, 1983b, 1983c and Spengler 1982b, 1982c.)

110

qC

.2 0

C 8

P

koidq

0.0 10.0 20.0 30.0 40.0 50.0 60.0DRIFI' INCLINATION (Degrees)

70.0 80.0 90.0

(a) Topopah Spring

C

Uz

t3

C3z

EC

UE-25a#1

USW G-4 |

............................. ^t

USW G-l(a)

,,,,,,,,,) .........USWG-(b) ''*-..,

..

..


70.0 80.0 90.0

(b) Calico Hills

Figure A-2. Plot of Fracture Frequency as a Function of Drift Inclination andDrillhole Not Including Fractures with Slickensides or HairlineFractures in the Topopah Spring and Calico Hills (Derived fromScott 1983a, 1983b, 1983c and Spengler 1982b, 1982c.)

111

C

0

> OJCD?

a °Mzo

t4

CO.-


70.0 80.0 90.0

(c) Bullfrog

qC

0 O

U O

Z O.

i;

rx#

q0.0 10.0 20.0 30.0 40.0 50.0 0

DRIFT INCLINATION (Degrees)70.0 80.0 90.0

(d) Tram

Figure A-2 (concluded). Plot of Fracture Frequency as a Function of DriftInclination and Drillhole Not Including Fractureswith Slickensides or Hairline Fractures in theBullfrog and Tram (Derived from Scott 1983a, 1983b,1983c and Spengler 1982b, 1982c.)

112

0

Cs'-4

.

0

z

tl o0E O

0¢ Vi

0!

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0DRIFT INCLINATION (Degrees)

80.0 90.0

(a) Topopah Spring

I~ I I .- I

0

N-

tzZQ.

USW G-4

... . /........ - -- ---------

UE-25a#1

USW G-1 (a)

..........----*----...... .,.....,,,,, *-.........'..CSW I (b) ... -

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 9DRIFT NCLINAllON (Degrees)

90.0

(b) Calico Hills

Figure A-3. Plot of Fracture Frequency as a Function of Drift nclination andDrillhole for the Fractures ot ncluding Hairline Fractures for

.the Topopah Sprin8 and Calico Hills (Derived from Scott 1983a,1983b, 1983c and Spengler 1982b, 1982c.)

113

S

. q

a

a:q

3 0

t -

0a

0.0 10.0 30.0 30.0 40.0 50.0 80.0 70.0

DRIFT INCLINATION (Degrees)80.0 90.0

(c) Bullfrog

a-4

0 0

U

c

a= O

3L .

W

wo

b q


70.0 80.0 90.0

(d) Tram

Figure A-3 (concluded). Plot of Fracture Frequency as a Function of DriftInclination and Drillhole for the Fractures NotIncluding Hairline Fractures for the Bullfrog andTram (Derived from Scott 1983a, 983b, 1983c andSpengler 1982b, 1982c.)

114

APPENDIX B

SUHARY OF AVAILABLE IFORHATION PERTAINING TO FRACTURECOATING AND FILLING FOR ALL THE TUFF UNITS EVALUATED

115-116

CLAY

CALCITE

MNO2

WHITE CG

DISCOLOREDERMCLAGONGE

CR SLICKSNONE

CLAY

CALCITE

MNO2

WHITE CTG

DISCOLOREDBRECCIA,GOUGE

OR SCKSNONE

Il ~~~~~~~~~~~~~~~~~~~~~~~~I

20 40 60 80PERCENT

Fractures with Inclination <45e(52 fractures)

(a) UE-25A#1

20 40 60PERCENT

s0

Fractures with Inclination >450(91 fractures)

CLAY

CALCITE

SILICA

MNO2

OXIDE

WHITE FILLSLCKifNON

NONE

. ~~~~~~~~~~~I

r.

CLAY

CALCITE

SIUCA

MNOz

OXIDE

WHITE FILLSLICKS, GOUGE

OR 8RECCIANONE

20 40 60PERCENT

80 20 40 60 80PERCENT

Fractures with Inclination <450(141 fractures)

(b) USW G-1(a)


CLAY

CALCITE

SILICA

MNO2

BIOTITE

RED-BROWN CGSOFT WHITE

MINERALSLICKS GGE

OR BRCCIANONE

CLAYCALCITE

SILICA

MNOz

BIOTITE

RED- BROWN CTGSOFT WHITE

MINERALSLICKS GOUGE

OR iECCIANONE

I~~~~~~~~~~~~~~~~~~~~~~~~

20 40 60 80PERCENT

20 40 60PERCENT

so

Fractures with Inclination <45-(18 fractures)

Fractures ith Inclination >45o(56 fractures)

(c) USW G-l(b)

Figure B-1. Summary of Fracture Coatings and Fillings for the Topopah Spring

Portion of UE-25a#1, USW G-1(a), and USW G-1(b) (Derived from

Spengler, 1982b; Scott, 1983b; Spengler, 1982c.)

-117

I

CALCITEMNOaIRON

WHITE CTGREDRWN CTG

GRAY CMNONE

ICALCITE

MNOaIRON

WHITE CTGRED-BROUMN MT

GRAY CTB

NCNE

I

I

20 4060 80PERCERT

20 40 60PERCENT

80



(a) U-25a#l

CLAYCALCITE

SILICAWHITE POWDER

DISCOLOREDNONE

h ICLAY

CALCITESILICA

WHITE POWDERDISCOLORED

NONE

20 40 60PERCENT

80 20 40 60 80PERCENT


Fractures with Inclination 45-(37 fractures)

(b) USW G-1(a)

Figure B-1 (concluded). Summary of Fracture Coatings and Fillings for theTopopah Spring Portion of USW GU-3, and USW G-4(Derived from Scott, 1983c; Scott, 1983a.)

118

CLAY

SILICASILTY WHITE

COATINGSILTY PINK

COATINGSLICKS GOUGE

OR RECCIANONE

20 40 60 80I PERCENT

CLAY

SILICASILTY WHITE

MATINGSILTY PINK

COATINGSLICKS GOUGE

OR IRECCIANONE

H~~~~~~~~~~~

.... I20 40 60

PERCENT80

Fractures with Inclination <450(7 fractures) -

(a) UE-25a#1

Fractures with Inclination >45'(44 fractures)

CLAY

MNO2

SILICA

NONE

20 40 60 80PERCENT

CLAY

. MNO2

SILICANONE l

. . . . . .

20 40 60PERCENT

80

Fractures with Inclination <45(1 fracture)

Fractures with Inclination >45'(9 fractures)

(b) USW G-l(a)

, .

IRON STAIN [20 40 60 80PERCENT

NO DESCRIPTION OF FRACTURECOATINGS AND FILLINGS

Fractures with-Inclination <450(2 fractures)

Fractures with Inclination >45°(3 fractures)

(c) USW G-l(b)

CALCITECLAY

SILICAWHITE POWDER

DISCOLORED

I

I' . . .

CALC ITECLAY

SILICAWHITE POWDER

DISCOLORED ,.. 120 40 60

PERCENT80 20 40 60

PERCENT80


(d) USW G-4

Fractures with Inclination >45-(33 fractures)

Note: Where the percentage of fracture coatings within a bar chart include 0or 1001 values that may be unclear, the vertical line indicating 0 or1001 is darkened.

Figure B-2. Summary of Fracture Coatings and Fillings for the CalicoHills Portion of UE-25a01, USW G-1(a), USW G-l(b), and USWG-4 (Derived from Spengler, 1982b; Scott, 1983b; Spengler,1982c; Scott, 1983a.)

119 '

IRON

9IarTTE

RED-BROWN CTG

WCOATNGSLICKS GOUGE

O bRECCANGE

20 40 60 80PERCENT

IRON

BIOTITE

RED-BROWN CTGWHITE SILTY

COATINGSLICKS GOUGE

OR BRECCIANONE

I

I

L__1. I - -20 40 60

PERCENT80


(a) U-25a#1


CLAY

MNO2

GRAY FILLSUCKSiGOUGEOR BRECCIA

NONE

II

+,. . .~~~~~~~~~~~~~~~~~~~~~~~~

CLAY

MNOt

GRAY FILLSLIC GOUGEOR B5ECCIA

NONE

I

20 40 60 60PERCENT

20 40 60PERCENT

80

Fractures with Inclination c45-(12 fractures)

Fractures with Inclination >45e(17 fractures)

(b) USW G-1(a)

MNO2 ORBLACK FILL.

SUCKS GOUGE IOR BECCIA

NONE ._ A . I

MNOX ORBLCCK FLL

SLICKS GOU5ECR REMIA _

NCE

. .

Ji20 40 60

PERCENT80 20 40 60 80

PERCENT



(c) USW G-1(b)

Figure -3. Sumary of Fracture Coatings and Fillings for the BullfrogPortion of US-25a#1, USW G-1(a), and USW G-l(b) (Derived fromSpengler, 1982b; Scott, 1983b; Spengler, 1982c.)

120

V4

MNOz

WHITE C7GRED-BRONN CTG

GRAY CTG

YELLOW CTG

GREEN CTGSUCKS GOUGE

OR BRENCIANONE

20 40 60 80PERCENTPERCENT



(d) USW GU-3

CLAYSILICAMNOt

ZEOLITEDISCOLORED

NONE

_ _~~~~__._ .

RI

CLAY

SILICA

MNOz

ZEOLITE

DISCOLORED

NONE

aI~~~~~~~~~I

< ~~~~~~~~~~~~~~~~~~~~20 40 60

PERCENT60 20 40 60

PERCENTs0

Fractures with Inclination 45-(9 fractures)

Fractures with Inclination >45o(50 fractures)

(e) USW G-4

Note: Where the percentage of fracture coatings within a bar chart include 0or 100. values that may be unclear, the vertical line indicating 0 or100% is darkened.

Figure -3 (concluded). Summary of Fracture Coatings and Fillings forthe Bullfrog Portion of USW G-3 and USW G-4(Derived from Scott, 1983a, 1983c.)

121

CLAYCALCITESILICA

SLICKSGOGEOR BRECIA

NONE

7 -. . . --

CLAY

CALCITESILICA

SWIKNONE

T . ,~~~~~~~~~~~~~

20 40 60PERCENT

80 20 40 60PERCENT

80



(a) USW G-l(a)

CLAY

CAWTEMNO2 OR

BLACK FLINGIRON

CHALCO PYRITESUCKS, GMJGE

OR BREOCIANONE

CLAYCALCITE

MNO ORPLACK FILLING

IRONCHALCOPYRITESUCKS GOUGE

OR WkCCIA- NONE I .

20 40 60PERCENT

80 20 40 60PERCENT

80



(b USW G-1(b)

Figure B-4. Summary of Fracture Coatings and Fillings for the Tram Portion ofUSW G-1(a) and USW G-1(b) (Derived from Scott, 1983b; Spengler,1982c.)

122

.

CLAY

CALCITE

MNO2

WHITE CTG

RED-BROWN CTG

GRAY CTG

YELLW CTG

GREEN CTG

NONENONE

CLAY

CALCITE

MNO2WHITE CTG

RED- BROWN CrG

GRAY CT

YELLOW CTG

GREEN CTGSLICKS GOUGE

OR BJECCIANONE

20 40 6 80PERCENT



(c) USW G-3

CLAY

CALCITE

SILICA

MN02

DISCOLCRED

NONE

CLAY

CALCITE

SILICA

MNO2

DISCOLORED

NONE

ERI

!. I 1 . I20 40 60

PERCENTs0 20 40 60

PERCENTs0

Fractures with Inclination.<45-(18 fractures)


(d) USW G-4

Figure B-4 (concluded). Summary of Fracture Coatings and Fillings for theTram Portion of USW G-3 and USW G-4 (Derived fromScott, 1983c; Scott, 1983a.)

123

CLAY

QUARTZDARK COATING-

MNO2

NO COATING l

OPEN FRACTURE

20 40 60 80PERCENT

(a) U12SCB#1

CLAY

QUARTZDARK COATING-

MNO2YELLOW-BROWN-

GRAY COATINGNO COATING

OPEN FRACTURE

20 40 60 80PERCENT

(b) U12gCB#2

Note: U12gCB#1 is oriented 600W, +20' from horizontal, TD = 36.0 m(118 ft). The number of fractures mapped - 156. U12gCB#2 is orientedN60W, +20- from horizontal, TD 40.2 m (132 ft). The number offractures mapped - 129.

Figure B-5. Summary of Grouse Canyon Fracture Coatings and Fillingsfor U12gCB#1 and U12gCB#2 (Derived from shom, 1981.)

124

a.

9.0 REFERENCES

Barr, G. E., "Reduction of the Well Test Data for Test Well USW H-i,Adjacent to Nevada Test Site, Nye County, Nevada," SAND84-0637,(Albuquerque, H: Sandia National Laboratories, May 1985).

Barton, N., R. Lien, and J. Lunde, "Engineering Classification of RockMasses for Design of Tunnel Support," Rock Mechanics, Vol. 6, o. 4,pp. 189-236, (1974a).

Barton, ., R. Lien, and J. Lunde, "Analysis of Rock Mass Quality andSupport Practice in Tunneling and a Guide for Estimating SupportRequirements," internal report, (Oslo, Sweden: Norwegian GeotechnicalInstitute, June 19, 174b).

Bieniawski, Z. T., "Rock Mass Classification in Rock Engineering,"Proceedings, Symposium on Exploration for Rock Engineering,(Johannesburg, South Africa, November 1976).

Branstetter, L. J., "ADINA Comparison of Three Candidate Emplacement Drift-Standoff Distances for the Horizontal Emplacement Scheme in Tuff,"memorandum, (Albuquerque, M: Sandia National Laboratories, December12, 1984).

Deere, D. U., "Technical Description of Rock Cores for EngineeringPurposes, Rock Mechanics in Engineering Geology," Rock Mechanics inEngineerint Practice, Vol. 1, o. 1, pp. 17-22, (1964).

Deere, D. U., and R. P. Miller, "Engineering Classification and IndexProperties for Intact Rock," Technical Report AFWL-TR-65-116, p. 186,(Albuquerque, UK: Air Force Weapons Lab, Kirtland Air Force Base,1966).

Ege, J. R., "Core Index, A Numerical Core Logging Procedure for EstimatingRock Quality," U. S. Geological Survey, in final review, (1983).

Eshom, E., written communication of core logs for U2gCB#1 and U12gCB#2,Nevada Test Site,(Mercury, V: Fenix and Scisson, 1981).

Hill, R. R., "Preliminary List of Some Reference Information Related toDesign," internal memorandum, (Albuquerque, NM: Sandia NationalLaboratories, June 18, 1985).

Hoek, E., and E. T. Brown, Underground Excavations in Rock, (London,England: The Institution of Mining and Metallurgy, 1980).

Holmes and Narver, Inc., data sheets that include uniaxial compressivestrength results on corp from U12g10#6, (April 4, 1978).

Holmes and Narver, Inc., Survey Department, written communication ondrillhole location information, Nevada Test Site, on data sheet titled"Area 25 and 29, Crater Flats INWSI Drillholes," (Drillhole survey datesreported are USW G-1, March 30, 1981; USW G-3, January 10, 1984; USWGU-3, April 23, 1982; UE25afl, April 13, 1984.), (March 20, 1985).

125

Hudson, J. A., and S. D. Priest, "Discontinuities and Rock Mass Geometry,"International Journal of Rock echanics, Mining. Science andGeomechanical Abstracts, Vol. 16, pp. 339-362 (December 1979).

Johnstone, J. K., R. R. Peters, and P. F. Gnirk, "Unit Evaluation at YuccaMountain, Nevada Test Site, Summary Report and Recommendations,"SAND83-0372, (Albuquerque, NM: Sandia National Laboratories, June1984).

Irier, Don, "The In Situ Welded Tuff Heater Experiment, Nevada Test Site:Experimental Site Stratigraphy, Preparation and Characterization,"internal memorandum, (Albuquerque, NM: Sandia National Laboratories,1980).

Lahoud, R. ., D. H. Lobmeyer, and . S. Whitfield, Jr., "Geohydrology ofVolcanic Tuff Penetrated by Test Well U-25b#1, Yucca Mountain, NyeCounty, Nevada," Water-Resources Investigations Report 84-4253,(Denver, CO: U.S. Geological Survey, 1984).

Langkopf, B. S., and Eric shom, "Site Exploration for Rock MechanicsField Tests in the Grouse Canyon Member, Belted Range Tuff, U12gTunnel Complex, Nevada Test Site," SAND81-1897, (Albuquerque, Nm:Sandia National Laboratories, February 1982).

Lappin, A. R., "Bulk and Thermal Properties of the Functional TuffaceousBeds Here Defined to Include the Basal Topopah Spring, All of theTuffaceous Beds of Calico Hills, and the Upper Portion of the ProwPass," internal memorandum, (Albuquerque, N: Sandia NationalLaboratories, March 26, 1982a).

Lappin, A. R., "Bulk and Thermal Properties for the Welded, DevitrifiedPortions of the Bullfrog and Tram Members, Crater Flat Tuff," internalmemorandum, (Albuquerque, N: Sandia National Laboratories, April 19,1982b).

Lappin, A. R., "Bulk and Thermal Properties of the Potential EmplacementHorizon Within the Densely Welded, Devitrified Portion of the TopopahSpring Member of the Paintbrush Tuff," internal memorandum, (Albu-querque, NM: Sandia National Laboratories, May 25, 1982c).

Lauffer, H., "Gebirgsklassifizierung fur den Stollenbau," Geologie undBauwesen, Vol. 24, pp. 46-51 (1958).

Mansure, A. J., and T. S. Ortiz, modified from Figure 3 (new NNWSI productnumber 144, February, 1985), "Preliminary Evaluation of the SubsurfaceArea Available for a Potential Nuclear Waste Repository at YuccaMountain," SAND84-0175, (Albuquerque, N: Sandia NationalLaboratories, December 1984).

Montazer, P., and W. . Wilson, "Conceptual Hydrologic Model of Flow inthe Unsaturated Zone, Yucca Mountain, Nevada," Water-ResourcesInvestigation Report 84-4345, (Denver, CO: U.S. Geological Survey,1984).

126

Nimick, F. B., S. J. Bauer, and J. R. Tillerson, "Recommended Matrix andRock Mass Bulk, Mechanical and Thermal Properties for ThermomechanicalStratigraphy of Yucca Mountain," Keystone Document 6310-85-1,(Albuquerque, NH: Sandia National Laboratories, October 1984).

Nimick, F. B., personal communication pertaining to ranges of matrixunconfined compressive strength for the candidate tuff units,(November 1984).

Price, R. H., "Analysis of Rock echanics Properties of Volcanic TuffUnits from Yucca Mountain, Nevada Test Site," SAND82-1315,(Albuquerque, NH: Sandia National Laboratories, August 1983).

Price, R. H., S. J. Spence, and A. K. Jones, "Uniaxial Compression TestSeries on Topopah Spring Tuff from USW GU-3, Yucca Mountain, SouthernNevada," SAND83-1646, (Albuquerque, NH: Sandia National Laboratories,February 1984).

Robison, J. H., "Groundwater Level Data and Preliminary Potentiometric-Surface Maps, Yucca Mountain and Vicinity, ye County, Nevada,"Water-Resources Investigations Report 84-4197, (Denver, CO: U. S.Geological Survey, 1984).

Rush, F. W., W. Thordarson, and D. G. Pyles, "Geohydrology of Test WellUSW H-1, Yucca Mountain, ye County, Nevada," Water-ResourcesInvestigations Report 84-4032, (Denver, CO: U. S. Geological Survey,1984).

Scott, R. B., written communication on fracture descriptions of USW G-4by M. Chornack, unpublished data, U. S. GeologicalSurvey, (1983a).

Scott, R. B., written communication on fracture descriptions of USW G-1by M. Castellanos, unpublished data, U. S. Geological Survey, (1983b).

Scott, R. B., written communication on fracture descriptions of USW G-3and USW GU-3 by M. Castellanos, unpublished data, U. S. GeologicalSurvey, (1983c).

Scott, R. B., written communication on oriented fracture data fromUSW G-3 and USW GU-3, U. S. Geological Survey, (1983d).

Scott, R. B., and M. Castellanos, "Stratigraphic and Structure Relationsof Volcanic Rocks in Drill Holes USW GU-3 and USW G-3, YuccaMountain, ye County, Nevada," Open-File Report 84-491, (Denver, CO:U. S. Geological Survey, 1984).

Scott, R. B., R. W. Spengler, S. Diehl, A. R. Lappin, and M. P. Chornack,"Geologic Character of Tuffs in the Unsaturated Zone at Yucca Mountain,Southern Nevada," SAND83-0143, Sandia National Laboratories, Albu-querque, NH, published in Role of the Unsaturated Zone in Radioactiveand Hazardous Waste Disposal, edited by James Mercer, (Ann Arbor, MI:Ann Arbor Science, 1983).

127

Spengler, R. W., written communication on core index record sheets fromUE-25a#1 recorded by . Eshom and Beadeard, unpublished data, U.S.Geological Survey, (July 21, 1980).

Spengler, R. W., written communication on core index record sheets fromUSW G-1 recorded by B. P. Chornack, unpublished data, U. S. GeologicalSurvey, (1981).

Spengler, R. W., "Preliminary Lithologic Log of USW G-4," U. S. GeologicalSurvey, (October 21, 1982a).

Spengler, R. W., written communication on fracture descriptions of U-25a#1by R. Livermore, unpublished data, U. S. Geological Survey, (1982b).

Spengler, R. W., written communication on fracture descriptions of USW G-1by R. W. Spengler and J. B. Warner, unpublished data, U. S. GeologicalSurvey, (1982c).

Spengler, R. W., written communication on core index record sheets fromUSW GU-3, unpublished data, U. S. Geological Survey, (September 13,1983a).

Spengler, R. W., written communication on core index record sheets fromUSW G-3 recorded by scobar, Parrish, Huckins, Cork, and DePaolis,unpublished data, U. S. Geological Survey, (September 13, 1983b).

Spengler, R. W., written communication on core index record sheets fromUSW G-4 recorded by . P. Chornack, unpublished data, U. S. GeologicalSurvey, (September 13, 1983c).

Terzaghi, Ruth D., "Sources of Error in Joint Surveys," Geotechnique,Vol. 15, pp. 287-304, (1965).

Terzaghi, K., Rock Defects and Loads on Tunnel Supports. Rock TunnelingWith Steel Supports, editors, Proctor, R. V. and T. White,(Youngstown, OH: Commercial Shearing and Stamping Co., 1946).

Teufel, L. W., personal communication of uniaxial compressive strengthtests from Tunnel Bed 5 in G-Tunnel, Nevada Test Site, (Hay 1985).

Thordarson, W., "Geohydrologic Data and Test Results from Well J-13, NevadaTest Site, Nye County, Nevada," Water-Resources Investigations Report83-4171, (Denver, CO: U.S. Geological Survey, 1983).

Thordarson, W., F. . Rush, and S. J. Waddell, "Geohydrology of Test WellUSW H-3, Yucca Mountain, Nye County, Nevada," Water-ResourcesInvestigations Report 84-4272, (Denver, CO: U.S. Geological Survey,1985).

Wickham, G. B., H. R. Tiedemann, and . H. Skinner, "Ground SupportPrediction Model - RSR Concept," Proceedings, First Rapid Transit andTunneling Conference, AIHE, pp. 43-64, (New York, 1972).

128

Zimmerman, R. ., and W. C. Vollendorf, Geotechnical Field Measurements,G-Tunnel, Nevada Test Site," SAND81-1971, (Albuquerque, NM: SandiaNational Laboratories, Hay 1982).

Zimmerman, R. M., personal communication of results of small-diameter-heater experiment that was conducted at G-Tunnel, (July 1985).

129-130

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Rockville, MD 20850

R. HarigParsons Brinkerhoff Quade &

Douglas, Inc.1625 Van Ness Ave.San Francisco, CA 94109-3678

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Jeffrey . NelsonRoy F. Weston2301 Research Blvd.Rockville, MD 20850

J. L. YowLawrence Livermore National

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R. B. ScottU.S. Geological SurveyMS 954Box 25046Denver Federal centerDenver, CO 80225

Paul Gnirk (5)RE/SPEC, Inc.P.O. Box 725Rapid City, SD 57709

T. R. ScoteseTudor Bin 12P.O. Box 4349Stanford, CA 94305

W. BartonNorwegian Geotechnical Institute

P.O. Box 40, TaasenOslo 8 Norway 0801

Peter KelsallIT Corporation2340 Alamo St. SESuite 306Albuquerque, N 87106

R. W. Spengler -

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Brenda BohlkeParsons Brinckerhoff1625 Van Ness Ave.San Francisco, CA 94109

J. D. Rockaway (4)University of Ho-Rolla125 MiningRolla, HO 65401

Z. T. BienawskiProfessor of Mineral Engineeringand Director, Pennsylvania Mining

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InstitutePennsylvania State University110 Mineral Sciences Bldg.

University Park, PA 16802

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B. S. Langkopf (10)R. R. PetersT. E. BlejwasE. A. KlavetterF. B. NimickB. M. Schwartz (2)R. H. ZimmermanJ. R. TillersonS. BauerJ. A. FernandezA. J. HansureR. E. StinebaughS. SinnockD. H. ZeuchL. D. TylerWHT Library (20)

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