ENVIRONMENTAL, GEOTECHNICAL, CONSTRUCTION SERVICES AND ANALYTICAL TESTING GEOTECHNICAL INVESTIGATION REPORT NEW ALIGNMENT FOR THE NORTH MANTECA TRUNK SEWER BSK PROJECT NO. G18-131-11L PREPARED FOR: NV5 1215 WEST CENTER STREET, SUITE 201 MANTECA, CALIFORNIA 95337 November 19, 2018
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ENVIRONMENTAL, GEOTECHNICAL, CONSTRUCTION SERVICES AND ANALYTICAL TESTING
GEOTECHNICAL INVESTIGATION REPORT
NEW ALIGNMENT FOR THE
NORTH MANTECA TRUNK SEWER
BSK PROJECT NO. G18-131-11L
PREPARED FOR:
NV5 1215 WEST CENTER STREET, SUITE 201
MANTECA, CALIFORNIA 95337
November 19, 2018
399 L indbergh Avenue
L ivermore CA 94551
P 925.315.3151
F 925.315.3152 www.bskassoc iates.com
November 19, 2018 BSK JOB No. G18-131-11L NV5 1215 West Center Street, Suite 201 Manteca, California 95337 ATTENTION: Ms. Jill Sylvester, PE ([email protected]) SUBJECT: Geotechnical Investigation Report
New Alignment for the North Manteca Trunk Sewer Manteca, California Dear Ms. Sylvester:
BSK Associates (BSK) is pleased to submit our geotechnical investigation report for the above-referenced
project. The enclosed report describes the geotechnical investigation performed and presents our
geotechnical recommendations for the design of the planned infrastructure and earthwork for the project.
In summary, it is our opinion that the site is suitable for the proposed construction provided that the
geotechnical recommendations presented herein are followed for design and construction of the project.
Due to the presence of shallow groundwater and predominantly loose to medium dense sand layers at
the site, excavations will need to be properly dewatered, sloped, and/or shored. Information on our
investigative methods, conclusions, and specific recommendations for the design of the planned
infrastructure and earthwork are contained in this report. Our report also discusses geologic hazards that
could affect the site during a future significant seismic event.
Conclusions and recommendations presented in the enclosed report are based on limited subsurface
investigation and our laboratory testing program. Consequently, variations between anticipated and
actual subsurface soil conditions may be found in localized areas during construction. If significant
variation in the subsurface conditions is encountered during construction, BSK should review the
recommendations presented herein and provide supplemental recommendations, if necessary.
Additionally, design plans should be reviewed by our office prior to their issuance for conformance with
the general intent of our recommendations presented in the enclosed report.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California iii
We appreciate the opportunity of providing our services to you on this project and trust this report meets
your needs at this time. If you have any questions concerning the information presented, please contact
us at (925) 315-3151.
Respectfully submitted, BSK Associates
Danaige Tower, EIT Carrie L. Foulk, PE, GE #3016 Senior Staff Engineer Senior Geotechnical Engineer Cristiano Melo, PE, GE #2756 Geotechnical Group Manager Distribution: Client (electronically via email) David Zensius, NV5 ([email protected])
5.1.4 Pipe Foundation ............................................................................................................... 14
5.1.4.1 Rock Ballast and Filter Fabric Option ................................................................ 14 5.1.4.2 Modified Caltrans Class 2 Permeable Material Option .................................... 15
5.1.5 Pipe Bedding and Embedment ......................................................................................... 15
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California vi
Plates and Appendices
PLATES
Plate 1 – Vicinity Map
Plate 2 – Site Plan
Plate 3 – Geologic Map
Plate 4 – Soil Profile at West Yosemite Avenue
APPENDIX A – Boring Logs
Plate A-1 – Unified Soil Classification System (ASTM D 2487/2488)
Plate A-2 – Soil Description Key
Plate A-3 – Log Key
Log of Borings B-9 through B-13
APPENDIX B – Laboratory Test Results
Plate B-1 – Atterberg Limits
Plate B-2 – Unconsolidated Undrained Triaxial Test
Plate B-3 through B-5 – Consolidated Undrained Direct Shear
Plates B-6 through B-10 – Sieve Analysis
Plate B-11 – R-Value Test
Corrosivity Analysis by CERCO Analytical (2 pages)
APPENDIX C – Subsurface Data from Previous Investigations
APPENDIX D –Summary of Compaction Recommendations
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 1
1. INTRODUCTION
This report presents the results of our geotechnical engineering investigation for the future North
Manteca Trunk Sewer project in Manteca, California. A Vicinity Map showing the location of the project
site is presented on Plate 1. Our investigation has been performed for and coordinated with NV5.
This report contains a description of our site investigation methods and findings, including field and
laboratory data. Based on these findings, this report presents conclusions regarding the geotechnical
concerns related to the planned improvements. It also provides recommendations for the design of the
planned infrastructure and construction considerations. Note that this final report supersedes the
information presented in our July 25, 2018 draft report for this project.
1.1 Project Description
The location of the planned infrastructure improvements is shown on the Site Plan, Plate 2. The project
will include mass grading and construction of utility lines up to 30 feet deep below the ground surface.
The utility lines that are to be constructed include a 12-inch potable water line approximately 1,300 feet
long, a 24-inch recycled water line approximately 5,100 feet long, a 54-inch trunk sewer line
approximately 4,200 feet long, and an approximately 150-foot long 36-inch trunk sewer line. The potable
water line is expected to be 5 to 7 feet below existing grade, the recycled water line is expected to be 5
to 13 feet below existing grade, and the 36- and 54-inch trunk sewer lines are expected to be 8 feet and
20 to 30 feet below existing grade, respectively. The new utility lines will be mostly constructed by cut
and cover methods except for two (2) trenchless crossings, which are anticipated to be installed by
microtunneling and/or bore and jack construction. These trenchless crossings will be as follows:
o Crossing #1 will be for the proposed 54-inch trunk sewer line and will be located where this utility
line will cross West Yosemite Avenue. The crossing will be approximately 25 to 30 feet deep below
existing grade and will cross under numerous existing underground lines running under West
Yosemite Avenue.
o Crossing #2 will be for the proposed 54-inch trunk sewer line and will be located where this utility
line will cross Airport Way. The crossing will be approximately 25 feet deep below existing grade
and will cross under several existing underground lines running under Airport Way.
As part of the project, the existing pavement section for Swanson Road will be demolished and
reconstructed. Also, numerous existing underground utility lines will be abandoned.
If the actual project differs significantly from that described above, specifically if the grading differs from
that we assumed above, we should be contacted to review and/or revise our conclusions and
recommendations presented in this report.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 2
1.2 Purpose and Scope of Services
The purpose of this investigation was to explore and evaluate the subsurface conditions at the site in order
to provide geotechnical input for the design and construction of the planned improvements and the
associated earthwork for this project. The scope of services, as outlined in our February 6, 2018 proposal
(File Number: GL18-16362), consisted of subsurface investigation, laboratory testing, engineering
analysis, and preparation of this report.
This investigation specifically excludes the assessment of site environmental characteristics, particularly
those involving hazardous substances.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 3
2. SITE INVESTIGATION
2.1 Previous Investigations
Previous investigations were performed near the project site in 2015 and 2016 by BSK Associates (BSK).
These investigations are presented in the following documents, which are listed from most recent to
oldest:
• BSK (2018), Geotechnical Investigation Report, North Manteca Trunk Sewer and Milo Candini
Drive Extension, 1215 West Center Street, Suite 201, Manteca, California, dated June 29, 2018
(File No. G16-127-11L)
• BSK (2016), Geotechnical Investigation Report, Manteca Water Quality Control Facility
Improvements, 2450 West Yosemite Avenue, Manteca, California, dated May 6, 2016 (File No.
G15-133-10L)
Plate 2 shows the locations of the previous borings proximate to the new alignment for the North Manteca
Trunk Sewer project and Appendix C presents relevant subsurface data and laboratory test results from
these reports. A discussion of the subsurface conditions encountered at the site is presented in the
“Subsurface Conditions” section of this report and took into consideration the subsurface data contained
in the previous reports listed above.
2.2 Current Investigation
A geotechnical field investigation was performed on June 21 and 22, 2018 to evaluate the subsurface
conditions at the site for the planned construction. This exploration consisted of drilling 5 borings (labeled
B-9 through B-13) at the approximate locations shown on Plate 2. The borings were drilled, using a truck-
mounted drill-rig to depths of approximately 35 to 40 feet below the existing ground surface (BGS).
Hollow-stem augers were used to drill the borings. Exploration GeoServices of San Jose, California was
subcontracted to provide drilling services. The borings were logged by a BSK field engineer who also
collected surficial bulk samples.
Prior to subsurface investigation, Underground Service Alert (USA) was contacted to provide utility
clearance. Several drilling permits were also obtained from the San Joaquin County Environmental Health
Department (County). Upon completion of the subsurface investigation, the borings were backfilled with
cement grout per the County permit requirements. The upper approximately 6 inches of borings located
in paved areas was patched with Quikrete. Excess soil cuttings generated during drilling were left in
unimproved areas of the site near the boring locations.
The locations of the borings were estimated by our field representative based on rough measurements
from existing features at the site. Elevations shown on the boring logs were based on the 90% Submittal
Plans provided to us by NV5, dated June 15, 2018, showing current ground surface elevations near our
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 4
borings. As such, the elevations and locations of the borings should be considered approximate to the
degree implied by the methods used.
Relatively undisturbed samples of the subsurface materials were obtained using a split barrel sampler
with a 2.5-inch inside diameter (I.D.) and a 3-inch outside diameter (O.D.) fitted with stainless steel liners.
In addition, a 1.4-inch I.D. Standard Penetration Test (SPT) sampler was driven at selected depths to obtain
disturbed samples. The samplers were driven 18 inches using a 140-pound, semi-automatic trip hammer
falling 30 inches. Blow counts for successive 6-inch penetration intervals were recorded on the boring
logs. After the samplers were withdrawn from the boreholes, the samples were removed, sealed to reduce
moisture loss, labeled, and returned to our laboratory. Prior to sealing the samples, strength
characteristics of the cohesive soil samples recovered were evaluated using a hand-held pocket
penetrometer. The results of these tests are shown adjacent to the sample locations on the boring logs.
Soil classifications made in the field from auger cuttings and samples were re-evaluated in the laboratory
after further examination and testing. The soils were classified in the field in general accordance with the
Unified Soil Classification System (Visual/Manual Procedure - ASTM D2488). Where laboratory tests were
performed, the designations reflect the laboratory test results in general accordance with ASTM D2487
as presented on Plate A-1. A Soil Description Key is presented on Plate A-2 and a key to the symbols used
in the boring logs is presented on the Log Key, Plate A-3. Sample classifications, blow counts recorded
during sampling, and other related information were recorded on the soil boring logs. Logs of borings B-9
through B-13 are presented in Appendix A. A discussion of the subsurface conditions encountered at the
site is presented in the “Subsurface Conditions” section of this report.
2.3 Laboratory Testing
Laboratory tests were performed on selected soil samples to evaluate their physical characteristics and
engineering properties. The laboratory testing program included dry density and moisture content, grain
size analysis, consolidated-undrained direct shear (DSCU), unconsolidated-undrained triaxial compression
(TXUU), and Resistance (R)-Value testing. Some of the testing was performed by Cooper Testing Labs of
Palo Alto, California. Most of the laboratory test results are presented on the individual boring logs. The
results of the TXUU, DSCU, grain size analysis, and R-Value tests are also presented graphically in Appendix
B.
Analytical testing was performed as part of our investigation on soil samples obtained from depths of
about 23½ and 13½ feet BGS at borings B-10 and B-12, respectively, to assist in evaluating the corrosion
potential of the on-site soils. The corrosivity testing was performed by CERCO Analytical of Concord,
California using ASTM methods as described in CERCO Analytical’s report. The corrosion results are
presented in Appendix B.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 5
3. SITE CONDITIONS
3.1 Site Description
As shown on Plate 2, the project site extends over a wide area, including a portion of the Manteca WQCF,
farming land, residential streets, and undeveloped land. The project limits are approximately bounded to
the south by the Manteca WQCF, to the north by farming land, and to the east by farming land and Airport
Way. West Yosemite Avenue crosses the middle of the utility alignment. The project site is relatively flat
with site elevations ranging from about 20 to 28 feet according to the recent topographic survey maps
provided by NV5. Several dirt embankments/farming access roads crisscross the site.
3.2 Geologic Setting
3.2.1 Area Geology
The site area is located in the Great Valley geomorphic province just east of the San Joaquin River which
forms a broad syncline with deposits of marine and overlying continental sediments, Jurassic to Holocene
in age. The thickness of the sediments increases to the west and reaches a thickness of as much as 20,000
feet on the west side of the San Joaquin Valley syncline. East of the site area are the Sierra Nevada
Mountains consisting of Mesozoic folded metamorphic rocks and Mesozoic plutonic rocks. To the west
are the Coastal Ranges characterized by north-south trending ridges and valleys that are typically highly
folded with numerous faults.
As shown on the Geologic Map, Plate 3, the site area is situated on the Pleistocene Modesto Formation
(Wagner, 1991)1, which consists primarily of sand and gravel in the fan areas while clay, silt, and sand are
dominant in the inter-fan areas. The formation thickness ranges from a thin layer on the east side of the
valley to approximately 150 feet thick in the central part of the basin (CDWR, 2003)2.
The geologic setting described above is consistent with the subsurface conditions encountered by the
previous and current borings performed at the site and the surrounding site vicinity, which are discussed
in the “Subsurface Conditions” section below.
3.2.2 Area Faults
Seismically induced ground motion at a site can be caused by earthquakes on any of the sources
surrounding the site. Deaggregation of the seismic hazard was performed by using the USGS Interactive
Deaggregation website (USGS, 2008)3. The deaggregation determination, at the maximum considered
1 Wagner, D.L., Bortugno, E.J., and McJunkin R.D. (1991), Geologic Map of the San Francisco - San Jose Quadrangle, California Geological Survey, Regional Geologic Map No. 5A. 2 California Department of Water Resources (CDWR, 2003), California’s Groundwater, Bulletin 118. 3 USGS (2008), 2008 Interactive Deaggregations, http://geohazards.usgs.gov/deaggint/2008/
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 7
SUMMARY OF GROUNDWATER ELEVATION DATA
Well Number Approximate Groundwater
Elevation (feet, MSL)1
Period of Groundwater Monitoring
MW-28 (T0607700558)
7.93 to 9.24 March to June 20152
MW-29 (T0607700558)
7.85 to 9.15 March to June 20152
MW-30 (T0607700558)
9.77 to 10.73 March to June 20152
MW-31 (T0607700558)
9.62 to 10.51 March to June 20152
MW-32 (T0607700558)
7.16 to 8.59 March to June 20152
MW-33 (T0607700558)
8.61 to 9.62 March to June 20152
MW-34 (T0607700558)
7.21 to 8.65 March to June 20152
MW-35 (T0607700558)
9.30 to 10.17 March to June 20152
MW-36 (T0607700558)
9.66 to 10.45 March to June 20152
MW-40 (T0607700558)
9.66 to 10.50 March to June 20152
Notes: 1. Groundwater elevation provided in the report entitled Second Quarter 2015 Sampling Report – Off-
Site Monitoring Well and Domestic Water Treatment System Sampling, Project Site “B”, Frank’s One Stop, 2072 West Yosemite Avenue, Manteca, Ca, Global ID No. T0607700558, dated July 23, 2015 by GHD, Inc. (GHD Job No. 03009-10006-37150) available on http://geotracker.waterboards.ca.gov.
2. Only data available.
The above is a general description of soil and groundwater conditions encountered at the site in the
previous and current borings. For a more detailed description of the soils encountered, refer to the boring
log data in Appendices A and C.
It should be noted that subsurface conditions can deviate from those conditions encountered at the
boring locations. If significant variation in the subsurface conditions is encountered during construction,
it may be necessary for BSK to review the recommendations presented herein and recommend
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 8
4. DISCUSSIONS AND CONCLUSIONS
Based on the results of our field investigation, it is our opinion that the planned infrastructure
improvements are feasible geotechnically and that the project site may be developed as presently
planned. This conclusion is based on the assumption that the recommendations presented in this report
will be incorporated into the design and construction of this project.
Additional discussions of the conclusions drawn from our investigation, including general
recommendations, are presented below. Specific recommendations regarding geotechnical design and
construction aspects for the project are presented in the “Recommendations” section of this report.
4.1 Underground Utility Lines
Based on our findings, we conclude that the currently planned underground utility alignments are feasible
provided the recommendations contained in this report are properly implemented during design and
construction. We anticipate that excavations for the utility lines can be made with standard earthwork
equipment, such as excavators, dozers, backhoes, and trenchers. Because the site is underlain primarily
by silty to poorly graded sand, shoring or sloping of cut faces and trench walls will be necessary to protect
personnel and to provide temporary stability.
4.2 Trenchless Utility Crossings
As discussed in the “Project Description” section of this report, two trenchless utility crossings are
planned. Near Crossing #1, borings B-9 and B-10 encountered loose to medium dense, poorly graded to
silty sand with minor sandy lean clay layers within the expected depth of the crossing. Gravel and cobble
layers were not encountered in borings B-9 or B-10 within the maximum depth explored (approximately
40 feet BGS). Free groundwater was observed at a depth of about 18 feet BGS during drilling of borings B-
9 and B-10.
Plate 4 presents our interpretation of the soil profile for Crossing #1 under West Yosemite Avenue. This
profile is for illustrative purposes only and is based on interpolation between and extrapolation beyond
the borings advanced at the site. As such, this cross section should be considered approximate. Actual
subsurface conditions may vary and will need to be confirmed in the field during construction.
Near Crossing #2, boring B-8 encountered primarily silty to poorly graded sand within the anticipated
depth of the crossing. However, a well graded sand layer was also encountered at a depth of about 7½
feet BGS. Gravel and cobble layers were not encountered in boring B-8 within the maximum depth
explored (approximately 40 feet BGS). The upper sand layers tend to be loose to medium dense but
becomes denser with depth. Free groundwater was observed at a depth of about 23 feet BGS during
drilling of boring B-8.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 9
Even though gravel layers were not encountered in our borings, gravel particles should be anticipated
within the sand layers. Sieve analysis and shear strength testing were performed on the samples collected
from our borings to aid in the design of the trenchless method(s) for the utility crossings. Based on our
findings, the planned trenchless crossings appear feasible from a geotechnical stand point provided
appropriate method(s) of installation are selected for the subsurface conditions anticipated. The
trenchless method(s) to be used should take into consideration the presence of shallow groundwater,
cohesionless soil layers, and cohesive soil layers underlying the site.
Note that the focus of our investigation for the trenchless crossings was to characterize the subsurface
conditions at these locations, evaluate their overall feasibility, and discuss possible constructability issues
that could occur during their construction. We understand that NV5 will design the trenchless crossings
and the excavation methods to be used. Due to the challenges associated with the presence of loose
cohesionless soils beneath the groundwater table, we recommend that experienced, specialty trenchless
contractor(s) be selected for the project.
4.4 Temporary Dewatering
As discussed in the “Subsurface Conditions” section of this report, groundwater can be shallower than 10
feet BGS near the project site’s vicinity. Therefore, we anticipate that excavations extending below this
depth will need to be continuously dewatered during construction.
4.5 Geologic and Seismic Hazards
4.5.1 Seismic Shaking and Faulting
We expect the site to be subjected to strong ground shaking during the life of the project. Therefore, the
design of pertinent underground and above-ground structures for the project should incorporate the
seismic design parameters presented in the “2016 CBC Seismic Design Parameters” section of this report
if applicable.
The site is not located within an Alquist-Priolo Earthquake Fault Zone and no mapped fault traces are
known to transverse the site. Therefore, we conclude that the potential for surface fault rupture to occur
across the site is very low.
4.5.2 Expansive Soils
The surficial soils are composed predominantly of fine grained silty sand with very low to low expansion
potential.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 10
4.5.3 Liquefaction and Lateral Spread
Soil liquefaction is a condition where saturated, granular soils undergo a substantial loss of strength and
deformation due to pore pressure increase resulting from cyclic stress application induced by
earthquakes. In the process, the soil acquires mobility sufficient to permit both horizontal and vertical
movements if the soil mass is not confined. Soils most susceptible to liquefaction are saturated, loose,
clean, uniformly graded, and fine-grained sand deposits. If liquefaction occurs, foundations and
improvements resting above or within the liquefiable layer may undergo settlements and/or a loss of
bearing capacity.
Due to the nature of this project, it was not in our scope to evaluate the liquefaction potential at our
exploration points. However, based on the findings from BSK’s 2018 and 2016 reports referenced in the
“Previous Investigations” section of this report, depending on the depth of the open cut excavations for
the project, we expect that there is a low to moderate potential for the utility lines to be subjected to
liquefaction-induced settlements during a design-level earthquake. Upwards of 6 inches of liquefaction-
induced settlements were estimated during these previous investigations.
Mitigation of liquefaction hazards is typically not considered an economically viable option for roadways
and underground utility improvements as the cost of mitigation is typically much greater than the cost of
post-seismic event repairs. However, if desired, ground improvement methods that could be used to
mitigate the liquefaction-induced settlement of the site improvements could include removal and
replacement (i.e., excavation and recompaction of on-site soil), stone columns (or similar methods such
as Impact Rammed Aggregate Piers, IRAP), and compaction grouting.
For this project, most of the 54-inch trunk sewer line is expected to be installed using cut and cover
excavations extending to depths of about 25+ feet BGS. These excavations will be backfilled with on-site
soils to a dense, firm state, thus eliminating the presence of loose soils susceptible to liquefaction within
the backfill zone. According to the previous investigations referenced above, most of the potential
liquefiable layers are located at depths of less than 30 feet. Therefore, we anticipate that the liquefaction
potential within areas of the site to undergo cut and cover excavation to depth of 25+ feet BGS would be
low after the planned 54-inch trunk sewer line is installed.
Lateral spread is a potential hazard commonly associated with liquefaction where extensional ground
cracking and settlement occur as a response to lateral migration of subsurface liquefiable material. These
phenomena typically occur adjacent to free faces such as slopes, creek channels, and levees. The project
site is relatively flat. The closest canals are located at least 200 feet and 600 feet from the northeast and
west limits, respectively, of the underground utility alignment and the canals appear to be shallower than
the anticipated depth of the potential liquefiable layers. Therefore, we conclude that the potential for the
project improvements to be adversely affected by lateral spread is low.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 11
4.5.4 Dynamic Compaction/Seismic Settlement
Another type of seismically induced ground failure, which can occur as a result of seismic shaking, is
dynamic compaction, or seismic settlement. Such phenomena typically occur in unsaturated, loose
granular material or uncompacted fill soils. The excavations for the planned utility lines will be 5+ feet
deep and will run underneath Swanson Road. Therefore, we conclude that the potential for seismic
settlement to occur underneath Swanson Road would be low because the excavation backfill below it
would be compacted to a dense, firm state.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 12
5. RECOMMENDATIONS
Presented below are recommendations for the design of the underground utility lines, trenchless utility
crossings, seismic considerations, earthwork, pavement sections, and construction considerations for this
project.
5.1 Manhole and Pipe Design
5.1.1 Foundation Bearing Support for Manholes and Pipes
Manhole foundations should consist of concrete bases placed on firm, undisturbed soil or compacted
backfill. For manholes, the bearing pressures at which foundation soils will experience no net increase in
pressure are estimated at about 600, 1,200, 1,800, and 2,400 pounds per square foot (psf), for depths of
5, 10, 20, and 30 feet BGS, respectively. These pressures assume a groundwater depth of 10 feet BGS. In-
place densities of 110 to 130 pounds per cubic foot (pcf) may be assumed for existing in-situ soils and for
compacted soil backfill for use in estimating the weight of soil removed and of backfill placed. Should
loads greater than the weight of the material excavated be imposed on the surface or subsurface soils,
we should be contacted to evaluate the bearing capacity at the location of the proposed construction.
The bottom of pipe and manhole subgrades should be firm and stable, free of debris, loose soil or mud,
and free-standing water prior to concrete or pipe placement. In addition, clay soils exposed at the bottom
of the manhole excavations should not be allowed to dry out prior to placing concrete.
At locations where loose sands or soft soils are encountered at the proposed pipe and manhole subgrade
elevations, or where the subgrade soils are disturbed during construction, stabilization of the excavation
bottom may be needed. This could consist of a layer of rock ballast wrapped in filter fabric or the modified
Caltrans Class 2 permeable material, as recommended in the "Pipe Foundation" section of this report.
Selection of the stabilization method to be used should be based on the severity of the conditions present
during construction.
5.1.2 Vertical Loads on Pipe
The pipe selected should be capable of supporting vertical loads due to the soil overburden (trench
backfill) and surcharge, including traffic loads. An in-place density of 130 pounds per cubic foot may be
assumed for the trench backfill, and Marston's Formula4 may be used. The vertical pressure on the pipe
due to an H-20 live load, as defined in the "American Iron and Steel Institute, Handbook of Steel Drainage
and Highway Construction Products", may be taken as follows:
4 Marston, A, and Anderson, A.P., "The Theory of Loads on Pipes in Ditches and Tests of Cement and Clay Drain Tile and Sewer Pipe." Iowa Eng. Sta., Bull. No. 31 (1913).
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 13
VERTICAL LOADS ON PIPE
Height of Cover Over Pipe (Feet) Vertical Pressure on Pipe (psf)
1 1,800
2 800
4 400
6 200
8 100
>8 Neglect live load
Additional surcharge loads on the pipe should be considered in the design if the loads are located above
the pipe or within a 1H:1V (horizontal to vertical) plane projected upwards from the spring line of the
pipe.
5.1.3 Manhole Walls
We anticipate that the walls of standard manholes 10 feet or less in depth are capable of resisting the
lateral earth pressures and surcharge lateral loads due to normal H-20 roadway traffic expected at this
site. For manholes deeper than 10 feet, or those exposed to loads greater than H-20 loads, the design of
walls should be checked using the at-rest pressures discussed below and the anticipated surface loads.
We consider manhole walls to be relatively rigid so that they cannot yield sufficiently to develop active
earth pressures. For this relatively unyielding wall condition, an at-rest lateral earth pressure of 60 pounds
per cubic feet (pcf), expressed as an equivalent fluid pressure (unit weight), may be used for design. This
recommended pressure does not include hydrostatic pressure. We recommend that the manhole walls
be designed to resist both at-rest and hydrostatic pressures. Due to the presence of shallow groundwater
at the project site, a drainage system would require use of continuous pumping, which in our opinion
would make this alternative less feasible than designing the walls to resist hydrostatic pressures. If the
groundwater rises above the bottom of the manholes, the soils would become buoyant and the at-rest
lateral earth pressure should be increased to 90 pcf, which includes hydrostatic pressure. We recommend
that the buoyant at-rest pressure be used below a depth of 10 feet BGS.
Surcharge loads adjacent to the manholes should also be included in the design of the manhole walls. A
rectangular distribution acting over the upper 10 feet of depth of the walls with a pressure equal to one-
half of the surcharge load may be used.
Lateral loads may be resisted by a combination of friction between foundation bottoms and the
supporting subgrade, and by passive resistance acting against vertical faces of the structures. An allowable
friction coefficient of 0.35 between the foundation and supporting subgrade may be used. For passive
resistance, an allowable equivalent fluid pressure (unit weight) of 300 pounds per cubic foot (pcf) may be
used against the opposite wall of the manholes. If the groundwater rises above the bottom of the
manholes, the soils would become buoyant and the passive soil pressure should be reduced to 200 pcf.
We recommend that the buoyant passive pressure be used below a depth of 10 feet BGS. The friction and
passive values include factors of safety of about 1½.
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Passive resistance in the upper one foot of the manhole walls should be neglected unless the ground
surface is confined by concrete slabs, pavements, or other such positive protection.
Section 1803.5.12 of the 2016 CBC requires that the design for foundation walls and retaining walls
supporting backfill heights greater than 6 feet include seismic earth pressures. Provided this requirement
applies to manhole walls, we recommend using seismic pressures of 30 pcf above a depth of 10 feet BGS
and 15 pcf below a depth of 10 feet BGS. These pressures are expressed as equivalent fluid pressures and
would be added to the wall design in addition to the static values presented above. The seismic earth
pressure should be applied as a triangular distribution with the resultant force acting at 1/3 times the wall
height above the base of the wall.
5.1.4 Pipe Foundation
Where pipe subgrade soils are firm and stable, free of debris, loose soil or mud, and free-standing water,
no pipe foundation material is needed. However, if loose sands or other soft or loose soils are encountered
at the proposed subgrade elevations for the pipeline and manholes, or where the subgrade soils are
disturbed during construction, we recommend that the pipe foundation consist of one of the options that
are listed below.
5.1.4.1 Rock Ballast and Filter Fabric Option
A layer of rock ballast wrapped in filter fabric (Mirafi 140N or equivalent) placed below the subgrade.
Before placing the rock ballast, the subgrade should be overexcavated a minimum of 9 inches below its
design elevation, followed by the placement of filter fabric.
The filter fabric should cover the entire width of the excavation at the locations where rock ballast is used,
and its seams should be fixed to the excavation walls before the placement of the rock ballast material.
Once these steps are accomplished, the overexcavated subgrade should be filled with rock ballast to
achieve a firm and stable surface. The rock ballast material should meet both of the following criteria:
• Consist of Class 1, Type B Permeable Material meeting the requirements of Section 68 of the 2010
Caltrans Standard Specifications; and
• Consist of crushed stone, or gravel, durable and free from slaking, or decomposition under action
of alternate wetting or drying.
Once the rock ballast is placed, the filter fabric seams should be detached from the walls of the excavation,
and wrapped around the rock ballast, and should overlap a minimum of one foot. Likewise, the filter fabric
seams for any consecutive sections of rock ballast placed longitudinally along the excavation should also
overlap a minimum of one foot.
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5.1.4.2 Modified Caltrans Class 2 Permeable Material Option
In lieu of using rock ballast and filter fabric, the pipe foundation could consist of a layer, a minimum of 9
inches in thickness, of Caltrans Class 2 permeable material meeting the gradation requirements of Section
68 of the 2010 Caltrans Standard Specifications with the following modifications:
• The percentage by weight passing the No. 10 sieve should range between 15 and 33 percent; and
• The percentage by weight passing the No. 50 sieve should be limited to no more than 1 percent.
5.1.5 Pipe Bedding and Embedment
Pipe bedding should be placed for a thickness of at least 6 inches below the bottom of pipes and should
consist of on-site fine grained silty sand and/or poorly graded sand or import soil that meets the
requirements discussed in the “Re-Use of On-site Soil and Imported Fill Material” of this report unless
otherwise noted by the City of Manteca's Standard Specifications. The same material used as pipe bedding
may be used as pipe embedment (also known as shading), which is the material typically placed from the
top of the pipe bedding to 12 inches above the top of the pipe.
If the on-site fine grained silty sand and/or poorly graded sand is used as pipe bedding and shading, it
should be free of clay/silt clods, organics, and deleterious matter. It is important that the bedding and
shading material be free-flowing to enable complete support and coverage around the pipes prior to
compaction. If clayey soil or predominantly silt soil is encountered in the trench excavations, such material
should not be used as pipe bedding and shading because it is very difficult to compact it under the pipe
haunches.
Coarse-grained sand, gravel, and drain rock should be avoided as pipe bedding and/or embedment unless
the material is fully enclosed in a filter fabric, such as Mirafi 140N or equivalent. Otherwise, the native
fine grained silty sand and poorly graded sand to be used as excavation backfill above the pipe
embedment could potentially migrate into coarse grained or gap graded material causing loss of ground
and resulting in ground settlement. This could result in pipe joint movement and pavement distress.
If desired, pipe bedding and embedment material may consist of the modified Caltrans Class 2
permeable material specified in Section 5.1.4.2 above.
5.2 2016 CBC Seismic Design Parameters
Due to potential earthquake motion resulting from nearby faults, seismic design factors should be
considered in the design of structures for the project unless such structures are exempted by the
California Building Code (CBC).
Based on previous investigations near the site vicinity, the loose to medium dense sand layers and silt
layers are susceptible to liquefaction. Therefore, according to Table 20.3-1 of ASCE 7-10, the site should
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be classified as Site Class F, which requires site response analysis. However, Sections 11.4.7 and 20.3.1 of
ASCE 7 state that for a short period (less than ½ second) structure on liquefiable soils, these factors may
be based on the assessment of the site class assuming no liquefaction. We anticipate structures for the
project will have a structural period of less than 0.5 seconds (BSK should be notified if that is not the case).
Therefore, Site Class D (stiff soil) is considered appropriate for this site.
Assuming a structural period less than 0.5 seconds for the proposed site structures, use of the 2016 CBC
mapped seismic design criteria is considered appropriate for this site and the following parameters should
be considered applicable for the design of structural improvements:
Seismic Design Category D Section 1613.3.5, 2016 CBC
MCEG peak ground acceleration adjusted for Site Class effects (g)
PGAM = 0.427 Section 11.8.3, ASCE 7-10
Definitions: MCER = Risk-Targeted Maximum Considered Earthquake MCEG = Maximum Considered Earthquake Geometric Mean *These seismic design parameters are based on the assumption that the proposed improvements have fundamental periods of less than about ½ second. If that is not the case, BSK should evaluate whether a site-specific response analysis is required.
As shown above, the short period design spectral response acceleration parameter, SDS, is greater than
0.5 and the long period design spectral response acceleration parameter, SD1, is greater than 0.2. These
values characterize the site as Seismic Design Category D as specified in Section 1613.3.5 of the 2016 CBC.
In accordance with Section 1613.3.5 of the 2016 CBC, each structure shall be assigned to the more severe
seismic design category in accordance with Table 1613.3.5(1) or 1613.3.5(2), irrespective of the
fundamental period of vibration of the structure.
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5.3 Trenchless Utility Crossings
5.3.1 Pipeline Materials
Pipelines installed using pull-in-place trenchless techniques such as horizontal directional drilling (HDD)
most commonly are made of steel or high-density polyethylene (HDPE). Other materials that are less
common for pull-in-place trenchless installations include ductile iron and polyvinyl chloride (PVC).
Pipelines installed using a jacked-in-place method such as guided boring, jack and bore and
microtunneling may include reinforced concrete, steel, vitrified clay jacking pipe, or Hobas (centrifugally
cast, glass-fiber-reinforced, polymer mortar) pipe. For future maintenance, alignment/grade tolerance,
and other reasons, some applications use an oversized steel casing pipe with the carrier pipe installed
inside the casing. The annular space is generally filled with sand or grout following installation of the
carrier pipe.
Pipe materials are generally selected based on owner preferences, strength, internal and external
corrosion, roughness, availability, cost, and compatibility with preferred installation techniques. We
understand that preferred pipe material types have not yet been established.
In an HDD installation, the product pipe may be exposed to extra abrasion during pullback. When installing
a steel pipe, a form of coating which provides a corrosion barrier as well as an abrasion barrier is
recommended during the operation, the coating should be well-bonded and have a hard, smooth surface
to resist soil stresses and reduce friction, respectively. A recommended type of coating for steel pipes is
mill applied Fusion Bonded Epoxy according to the 2015 Caltrans Guidelines and Specifications for
Selection of an appropriate trenchless installation technique for a particular location usually depends on
a number of factors including pipe material type and size, length and depth of run, subsurface conditions,
alignment and grade control tolerances, space constraints in the site vicinity, and environmental factors.
The selected trenchless method(s) should take into consideration the presence of shallow groundwater,
cohesionless soil layers, and cohesive soil layers underlying the site.
5.3.3 Minimum Depth of Cover
Based on the 2015 Caltrans Guidelines and Specifications for Trenchless Technology Projects, minimum
depths of cover of 10 and 15 feet BGS at the crossings should be considered. However, the actual depth
of cover selected will be influenced by the trenchless method selected.
5 Caltrans (2015), Caltrans Encroachment Permits, Guidelines and Specifications for Trenchless Technology Projects, dated January 2015.
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5.3.4 Settlement Monitoring
Care should be exercised during installation of the trenchless crossings to avoid excessive loss of ground
which could propagate to the surface and cause settlement and distress to the pavement and surrounding
improvements at West Yosemite Avenue and Airport Way. Ground surface settlement monuments should
be established along and within a zone extending at least 30 feet to either side of the planned path of the
crossings at West Yosemite Avenue and Airport Way. The monuments should be located along the
shoulders and center left turn lane of West Yosemite Avenue and the shoulders and center of Airport
Way. The elevation of the monuments should be read prior to the start, throughout, and after the
trenchless operation is completed. During the trenchless operation, the monuments should be read on a
daily basis. Monitoring records should be made available to the City of Manteca and its consultants on a
daily basis during construction. If significant movement of the ground surface is noticed during the
trenchless operation, measures should be immediately taken to address any further loss of ground,
including, but not limited to, properly backfilling and abandoning the drill hole with grout or bentonite to
prevent future subsidence.
5.3.5 Contractor Selection
The successful construction of the trenchless crossings will be substantially determined by the experience
and performance of the specialty contractor(s) retained to perform the work. We recommend the use of
specialty contractor(s) with a minimum of 5 to 10 years of continuous construction experience in similar
drilling conditions on projects of similar scope (i.e., pipe diameter, pipe material, length, and depth) with
the specific trenchless method to be used by that contractor for this project. Contractor(s) to be
considered in the bidding process should provide examples of trenchless projects they have successfully
completed in the past 5 years installing similar utilities in similar conditions. The example projects should
note instances when things went wrong during particular projects and how they were remediated during
construction.
5.4 Earthwork
Earthwork at this project will generally consist of the following:
• Mass grading;
• Subgrade preparation;
• Placement of crushed rock underneath manholes;
• Excavation and backfill for the manholes and existing utilities to be relocated or abandoned, and
new underground utility lines; and
• Subgrade preparation and placement of aggregate base for the reconstruction of Swanson Road;
and
• Excavation and backfill of entry and exit shafts for trenchless excavation techniques.
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We anticipate that the required grading will consist of cuts and backfills up to about 30 feet deep. Final
site grades are expected to remain relatively unchanged throughout the site. BSK should review the final
grading plans for conformance to our design recommendations prior to construction bidding. In addition,
it is important that a representative of BSK observe and evaluate the competency of existing soils or new
fill during construction. In general, soft/loose or unsuitable materials encountered should be over
excavated, removed, and replaced with compacted engineered fill material.
Site preparation and grading for this project should be performed in accordance with the site-specific
recommendations provided below. A summary of soil compaction recommendations for this project is
presented in Appendix D. Additional earthwork recommendations are presented in related sections of
this report.
5.4.1 Existing Utilities
Active or inactive utilities within the construction area should be protected, relocated, or abandoned.
Pipelines that are 2 inches or less in diameter may be left in place provided they are cut off and capped.
Pipelines larger than 2 inches in diameter should be removed or filled with a 1-sack sand-cement slurry
mix. Active utilities to be reused should be carefully located and protected during demolition and
construction activities at the site.
5.4.2 Site Preparation, Grading, and Compaction
Prior to the start of grading and subgrade preparation operations, the site should first be cleared and
stripped to remove all surface vegetation, organic-laden topsoil and debris generated during the
demolition of existing site improvements located within the project limits. Stripped topsoil from vegetated
areas may be stockpiled for later use in landscaping areas; however, this material should not be reused
for engineered fill.
Following stripping and removal of deleterious materials, the upper 12 inches (minimum) of the areas of
the site to receive fill should be scarified, moisture conditioned, and recompacted as indicated in Appendix
D, unless otherwise indicated by a BSK representative. Scarification and recompaction should extend
laterally a minimum of 2 feet beyond the limits of new fills, where achievable. If any undocumented fill is
encountered, the fill should be evaluated by a BSK representative and, if deemed necessary, removed and
replaced as engineered fill. All fills should be compacted by mechanical means in lifts of 8-inch maximum
uncompacted thickness. Jetting or ponding should not be permitted as a backfill compaction method
because these methods could result in very poor to poor relative compaction (due to the lack of
mechanical compaction) and cause significant settlement to occur at the site surface in the future. A
summary of compaction requirements for the project is presented in Appendix D. Laboratory maximum
dry density and optimum moisture content relationships should be evaluated based on ASTM Test
Designation D1557 (latest edition).
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Subgrade soils, fill, and backfill, should be compacted to a minimum of 90 percent compaction at near
optimum moisture content. In paved areas, the upper 12 inches of the subgrade, and the aggregate base
above it, should be compacted to a minimum of 95 percent compaction at near optimum moisture
content. Where clayey soils are present, the soils should be moisture conditioned to at least 2 percent
above the optimum moisture content and the subgrade for pavements may be compacted to a minimum
of 93 percent compaction.
Most of the planned underground utility lines will be constructed using cut and cover excavation. These
temporary excavations are expected to be up to 30+ feet deep BGS. It will be critical to properly compact
the backfill for these excavations to reduce the potential for significant settlements to occur within their
limits. Because any settlement in these excavations will be differential relative to areas of the site not to
be excavated, consideration should be given to compacting all backfill below a depth of 7 feet below
finished grade to a minimum of 95 percent compaction where new or existing surface improvements are
located within a 1H:1V projection line extending up from the bottom of trench excavations.
Where access for compaction testing in deep excavations is limited due to trench stability, safety, and
other access concerns, sand-cement slurry or controlled density fill (CDF) may be considered as an
alternative to soil backfill if permitted by the City of Manteca. If this type of backfill material is used, the
utility lines should be anchored to prevent the pipe from floating. The slurry or CDF should be properly
vibrated to allow backfilling under the spring line of the pipes affected. If these types of backfill are
needed, consideration should be given to using the on-site sand material as part of the slurry or CDF.
Sand-cement slurry backfill typically consists of a 1- or 2-sack mix. CDF typically consists of a mixture of
cement, fly ash, coarse and fine aggregate, an air entrainment admixture and water. It should have a 28-
day compressive strength in the range of 50 pounds per square inch (psi), density in the range of 115 to
145 pounds per cubic foot (pcf), and a set time on the order of 4 to 6 hours. Such materials are locally
produced, and have been used successfully in several local jurisdictions where fast-setting, low-strength
backfill is needed. The proposed materials and method of construction should be reviewed by the City
and BSK prior to their approval and use.
All site preparation and fill placement should be observed by a BSK representative. During the stripping
process, it is important that our representative be present to observe whether any undesirable material
is encountered in the construction area and whether exposed soils are similar to those encountered
during our subsurface investigation.
5.4.3 Re-Use of On-site Soil and Imported Fill Material
From a geotechnical standpoint only, excavated on-site soils should considered suitable for re-use as
general engineering fill and backfill, provided organic materials are removed. Particles larger than 3 inches
within the on-site soils to be used as engineer fill should either be removed and disposed offsite or broken
down to 3 inches or less. Nesting (i.e., concentration) of larger particles should be avoided to reduce the
potential that this could create voids and allow future settlement in the overlaying fill/backfill.
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Maximum particle size for fill material should be limited to 3 inches, with at least 90 percent by weight
passing the 1-inch sieve. Proper granular bedding and shading should be used beneath and around new
utilities except for segments to be installed using trenchless methods. In addition, imported fill should
adhere to the above gradation recommendations and conform to the following minimum criteria:
IMPORT FILL CRITERIA
Plasticity Index 15 or less
Liquid Limit Less than 30%
% Passing #200 Sieve 8 % – 40%
Corrosivity Refer to the “Corrosion” section of this report
Imported fill material should not be any more corrosive than the on-site soils and should not be classified
as being more corrosive than "moderately corrosive." If the imported fill is used to build the roadways off
of Swanson Road, it should have a minimum R-Value of 40.
Prior to transporting proposed import materials to the site, the contractor should make representative
samples of the material available to the geotechnical engineer at least 5 working days in advance to allow
the engineer enough time to confirm the material meets the above requirements. If prior corrosion testing
results are not available for the proposed import fill materials, then the samples should be made available
to the geotechnical engineer at least 10 working days in advance so that corrosion testing may be
conducted if this testing is deemed necessary. All on-site or import fill material should be compacted to
the recommendations provided for engineered fill in Appendix D.
5.4.4 Weather/Moisture Considerations
If earthwork operations and construction for this project are scheduled to be performed during the rainy
season (usually November to May) or in areas containing saturated soils, provisions may be required for
drying and/or stabilizing the soil through the use of scarification and air drying, geotextile fabric and dryer
soils, and/or via admixtures, such as lime- or cement-treatment of the soil prior to compaction.
Conversely, additional moisture may be required during dry months. Water trucks should be made
available in sufficient numbers to provided adequate water during earthwork operations.
5.4.5 Excavation, Shoring, and Backfill
We anticipate that excavations for new utility lines, manholes, entry and exit shafts, and the pavement
subgrade for the roadways off of Swanson Road can be made with standard earthwork equipment, such
as excavators, dozers, backhoes, and trenchers. Because the site is underlain primarily by silty to poorly
graded sand, shoring or sloping of cut faces and trench walls will be necessary to protect personnel and
to provide temporary stability.
All excavations made at the site should be evaluated to monitor stability prior to personnel entering them.
All trenches and excavations should conform to the current OSHA requirements for work safety. Based on
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our findings, we anticipate that a maximum slope inclination of 1½H:1V for excavations up to 20 feet in
depth could be used at this site. However, it is the contractor’s responsibility to follow OSHA temporary
excavation guidelines and grade the slopes with adequate layback or provide adequate shoring and
underpinning of existing structures and improvements, as needed. Slope layback and/or shoring measures
should be adjusted as necessary in the field to suit the actual conditions encountered in order to protect
personnel and equipment within excavations.
Where the stability of adjoining embankments or structures could be endangered by excavation
operations, support systems such as shoring, bracing, or underpinning may be required to provide
structural stability and to protect personnel working within the excavation. The design and installation of
shoring, bracing, or underpinning required for the project should be the responsibility of the contractor
and should be designed by a professional engineer registered in the State of California. We recommend
that the proposed shoring, bracing, and underpinning system design be submitted (along with the
appropriate design calculations) in advance for review. The purpose of the review would be to evaluate
whether proper soil parameters have been used and to confirm whether the anticipated deflections are
within the tolerance established by the owner or its designer.
Due to the presence of predominantly fine grained silty sand and poorly graded sand layers underlying
the site, shored excavations will likely require use of continuous or solid-type shoring during excavation,
such as sheet piles. If soldier piles are to be used, continuous lagging will be necessary to prevent caving
of the excavation walls. Discontinuous, conventional shoring, such as trench boxes and hydraulic shores
with plywood/steel plates ("speed shores"), may not adequately support excavation walls because the
sand may not stand vertically long enough to move shoring into place following excavation. Discontinuous
shoring systems are not recommended for use in entry and exit shafts for trenchless excavation methods.
Shoring should be removed as the excavations are backfilled. Shoring should be designed to resist earth
pressures exerted by the retained soil plus any applicable surcharge loading, such as construction
equipment and stockpiles.
Excavations should be properly dewatered as discussed in the “Temporary Dewatering” section below.
Construction equipment and soil stockpiles should be set back a minimum horizontal distance of H away
from the edge of excavations, where H is equal to the depth of the excavation. This setback distance also
applies to shored excavations unless the shoring design takes into account any surcharge loads associated
with the construction equipment and stockpiles.
Care should be taken during construction to reduce the impact of trenching on adjacent structures and
pavements. Excavations should be located so that no structures, foundations, and slabs, existing or new,
are located above an imaginary plane projected 1H:1V upward from any point in an excavation unless the
excavation is properly shored and excavated in stages. If structures are located within this 1H:1V project
line, the shoring should be designed to handle the surcharge loading from the adjacent structure and
allow no horizontal movement of the excavation. Prior to the installation of the shoring and excavation,
monitoring points should be established immediately behind the shoring, at midway points between the
adjacent structure and the shoring, and at the edge of the adjacent structure. These points should be
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 23
surveyed daily during installation of the shoring and staged excavation. If any lateral movement is
detected, the excavation operation should be stopped immediately and measures should be taken to halt
further movement, such as placing a fill buttress in front of the shoring. The shoring design should then
be reevaluated and revised as needed. The design and installation of shoring, bracing, or underpinning
required for the project should be the responsibility of the contractor and should be designed by a
professional engineer registered in the State of California.
During wet weather, appropriate provisions, such as the use of earthen berms, should be made to prevent
water runoff from ponding adjacent to the top of excavations and/or flowing over the sides of the
excavations, otherwise the excavations side walls and/or slopes could be compromised. All runoff should
be collected and disposed of outside the construction limits. Backfill for excavations should be compacted
as noted in Appendix D. Special care should be taken in the control of excavation backfilling under
structures and pavements. Poor compaction may cause excessive settlements resulting in damage to
overlying structures and the pavement structural section.
5.4.6 Temporary Dewatering
Cut and cover excavation methods are planned for most of the new utility lines. These excavations will
extend to depths of 30+ feet BGS. We expect that excavations deeper than about 10 feet BGS (this is
equivalent to groundwater elevations of about 14 feet near boring B-3 (2016) and 12 feet near boring B-
8 (2016) will need to be continuously dewatered during construction depending on the time of the year.
However, based on monitoring well data and previous borings near the site vicinity, it is possible that
groundwater could be shallower than 10 feet BGS at the site during construction of the project,
especially during the raining season (typically November through May). The soils encountered within
the maximum depth of our exploration (about 40 feet BGS) consisted primarily of silty to poorly graded
sand layers, but lesser amounts of clay and silt layers were also present. Depending on their fines content
(i.e., amount of material passing the No. 200 sieve), sand layers typically have much higher transmissivity
rates than clay and silt layers. Groundwater should be lowered and maintained at least 2 feet below the
bottom of the planned excavations in order to maintain the undisturbed state of the supporting soils and
to allow proper compaction of backfill after below-grade structures and utility lines are installed. After
completion of all below-grade structures and utility lines, the dewatering operations may be terminated
to allow the groundwater table to return to its natural level.
During Phase 1 of construction (2016-2017) for the Family Entertainment Zone (FEZ) Infrastructure project
located approximately one mile south of the North Manteca Trunk Sewer project, dewatering was
employed to construct a 48-inch trunk sewer with open trench construction method. The FEZ trunk sewer
depth varied between approximately 20 and 25 feet BGS. We understand that with all the dewatering
pumps operating over the entire approximately 4,400-foot alignment, an average dewatering volume of
3 to 3½ million gallons per day was observed.
We anticipate that dewatering in the project area will be performed in stages and can be performed using
deep wells, well points, sumps, drains, and open pumping. However, because the subsurface conditions
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consist of loose to medium-dense sand, slope stability and boiling at the bottom of the excavations could
pose a problem. The contractor should be fully responsible for developing and implementing a
dewatering program, including doing their due diligence to estimate the water quality and volume to
dewater this project. This should include making any necessary adjustments to the dewatering program
during construction based on actual field conditions encountered.
The successful implementation of the dewatering program for this project will be substantially
determined by the experience and performance of the contractor retained to perform the dewatering.
Therefore, we recommend that the general contractor for the project be required to retain the services
of a specialty dewatering subcontractor to review the anticipated subsurface conditions, and develop
and implement a proper dewatering program for the project. We recommend the use of a specialty
dewatering subcontractor with a minimum of 5 to 10 years of continuous construction experience in
similar subsurface conditions on projects of similar scope (i.e., depth of excavations, proximity to and type
of existing structures and utility lines, etc.). The dewatering subcontractor selected should provide
examples of dewatering for projects they have successfully completed in the past 5 years under similar
subsurface conditions and similar scope to this project. The example projects should note instances when
things went wrong during particular projects and how they were successfully remediated during
construction.
Temporary dewatering may cause ground subsidence that could result in adverse settlement of structures
near the areas being dewatered. Therefore, the dewatering subcontractor should evaluate the need to
install observation wells between existing structures and the dewatering activities to monitor changes in
groundwater levels. If dewatering-induced settlements are anticipated by the dewatering subcontractor,
it should consider implementing modifications to its dewatering program and possibly underpinning
existing structures (if allowed by the owner and/or its consultants). If underpinning is anticipated by the
dewatering subcontractor, prior to implementation of the underpinning, the project owner and its
consultants should review the underpinning plans to evaluate the assumptions made in the underpinning
design. This review should not be considered as relieving the dewatering subcontractor from full
responsibility for the underpinning plans and its satisfactory implementation.
In addition, consideration should be given by the dewatering subcontractor to installing ground surface
settlement monuments adjacent to structures located near areas of the site to be dewatered and
monitoring these monuments on a regular basis during dewatering activities. Monitoring records should
be made available to the owner and its consultants on a regular basis during construction. If significant
movement of the ground surface is noticed during or after the dewatering operation is completed,
measures should be immediately taken by the dewatering subcontractor to arrest the settlement. The
dewatering subcontractor should then develop and implement a plan for successfully mitigating the
settlement.
Consideration should also be given to performing video documentation and an existing conditions survey
of the nearby residences prior to and immediately after construction of the new underground utility lines
to be dewatered. The intent would be to capture existing conditions and monitor distress prior to and
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 25
during construction. This survey could be helpful if there are claims of damage by the nearby residents as
a result of the construction operations.
5.5 Reconstruction of Swanson Road
5.5.1 Pavement Section
We performed a Resistance (R)-Value test on a bulk sample collected at the ground surface of boring B-
11, which resulted in an R-Value of 59. Previous geotechnical investigations near the site have obtained
R-Value test results ranging from 50 to 75. Due to the potential variability of the silt content contained in
the surficial soils at the site, we recommend using an R-Value of 40 for design of the new pavement section
for Swanson Road.
Based on our discussions with NV5, we understand that Traffic Index (TI) values of 5.0 to 6.0 will be used
to design the pavement section for new residential driveways, while a TI value of 11 will be used to design
the pavement section for Swanson Road. The recommended pavement section is presented in the table
below and includes a factor of safety of 0.2 feet as per the Caltrans Design Manual.
ASPHALT CONCRETE PAVEMENT DESIGN FOR NEW RESIDENTIAL DRIVEWAYS
AND THE RECONSTRUCTION OF SWANSON ROAD
(R-VALUE = 40)
Traffic Index AC AB
5.0 2.5 5.0
5.5 3.0 5.0
6.0 3.0 6.0
11.0 7.0 12.5
Notes: Thicknesses shown are in inches. AC = Type A Asphalt Concrete AB = Class 2 Aggregate Base (Minimum R-Value = 78)
5.5.2 Construction Considerations
We recommend that the subgrade soil over which the future roadways are to be constructed be moisture
conditioned and compacted according to the recommendations in Appendix D. Subgrade preparation
should extend a minimum of 2 feet laterally beyond the road embankment limits.
On-site surficial sandy soils are considered suitable for use as engineered fill for the roadways. However,
care should be exercised during construction to avoid using soils resulting from deep excavations at the
site because these excavations will extend into layers that are sometimes composed primarily of silt and
clay, which typically have a much lower R-Value than the predominantly sand soils present at the ground
surface.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 26
The pavement should be sloped and drainage gradients maintained to carry all surface water to
appropriate collection points. Surface water ponding should not be allowed anywhere on the site during
or after construction.
In addition, we recommend that all pavements conform to the following criteria:
• All excavation backfills should be properly placed and adequately compacted to provide a
stable subgrade, in accordance with the compaction recommendations in Appendix D;
• An adequate drainage system should be provided to prevent surface water or subsurface
seepage from saturating the subgrade soil;
• The asphalt concrete and aggregate base materials should conform to Caltrans Specifications,
latest edition; and
• Placement and compaction of pavements should be performed and tested in accordance to
appropriate Caltrans test procedures.
5.5.3 Reuse of On-site Asphalt Concrete
Existing asphalt concrete may be pulverized and mixed with the underlying gravel layer (i.e., aggregate
base) for use as general engineered fill if it meets the gradation requirements discussed in the “Re-Use of
On-site Soils and Imported Fill Material” section of this report.
Consideration should also be given to processing the existing asphalt concrete and underlying base for re-
use as Caltrans Class 2 aggregate base for provided it meets the gradation, R-Value, durability index, and
sand equivalent requirements of Section 26 of the 2015 Caltrans Standard Specifications, unless otherwise
indicated by the Geotechnical Engineer-of-Record during construction.
5.6 Corrosion
Samples of the subsurface soils at depths of approximately 13½ and 23½ feet below the existing ground
surface at borings B-12 and B-10, respectively, were submitted for corrosion testing. The samples were
tested by CERCO Analytical, a State-certified laboratory in Concord, California, for redox potential, pH,
resistivity, chloride content, and sulfate content in accordance with ASTM test methods. The test results
are presented at the end of Appendix B. Also included is the evaluation by CERCO Analytical of the
corrosion test results. Because we are not corrosion specialists, we recommend that a corrosion specialist
be consulted for advice on proper corrosion protection for underground piping which will be in contact
with the soils and other design details. Note that Appendix C also includes previous corrosivity test results.
Based upon the resistivity measurements, the samples tested are classified as "moderately corrosive to
corrosive" by CERCO Analytical. They recommend that all buried iron, steel, cast iron, ductile iron,
galvanized steel, and dielectric coated steel or iron be properly protected against corrosion depending
upon the critical nature of the structure. They also recommend all buried metallic pressure piping, such
as ductile iron firewater pipelines, should be protected against corrosion.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 27
The above are general discussions. A more detailed investigation may include more or fewer concerns,
and should be directed by a corrosion expert. BSK does not practice corrosion engineering. Consideration
should also be given to soils in contact with concrete that will be imported to the site during construction,
such as topsoil and landscaping materials. For instance, any imported soil materials should not be any
more corrosive than the on-site soils and should not be classified as being more corrosive than
"moderately corrosive." Also, on-site cutting and filling may result in soils contacting concrete that were
not anticipated at the time of this investigation.
5.7 Plan Review and Construction Observation
We recommend that BSK be retained by the Client to review the 100 percent complete construction plans
and specifications before they go out to bid. It has been our experience that this review provides an
opportunity to detect misinterpretation or misunderstandings of our recommendation prior to the start
of construction.
Variations in soil types and conditions are possible and may be encountered during construction. To
permit correlation between the soil data obtained during this investigation and the actual soil conditions
encountered during construction, we recommend that BSK be retained to provide observation and testing
services during site earthwork. This will allow us the opportunity to compare actual conditions exposed
during construction with those encountered in our investigation and to provide supplemental
recommendations if warranted by the exposed conditions. Earthwork should be performed in accordance
with the recommendations presented in this report, or as recommended by BSK during construction. BSK
should be notified at least two weeks prior to the start of construction and prior to when observation and
testing services are needed.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 28
6. ADDITIONAL SERVICES AND LIMITATIONS
6.1 Additional Services
The review of plans and specifications, and field observation and testing during construction by BSK are
an integral part of the conclusions and recommendations made in this report. If BSK is not retained for
these services, the Client will be assuming BSK’s responsibility for any potential claims that may arise
during or after construction due to the misinterpretation of the recommendations presented herein. The
recommended tests, observations, and consultation by BSK during construction include, but are not
limited to:
• review of plans and specifications;
• observations of site grading, including stripping and engineered fill placement;
• observation of grading activities for reconstruction of Swanson Road;
• observation of grading activities for cut and cover utility construction;
• observation of trenchless utility crossing construction; and
• in-place density testing of fills, backfills, and finished subgrades.
6.2 Limitations
The recommendations contained in this report are based on our field observations and subsurface
explorations, limited laboratory tests, review of available geologic maps and publications, review of
previous investigations near the site, and our present knowledge of the proposed construction. It is
possible that soil conditions could vary between or beyond the points explored. If soil conditions are
encountered during construction that differ from those described herein, we should be notified
immediately in order that a review may be made and any supplemental recommendations provided. If
the scope of the proposed construction, including the proposed loads or structural locations, changes
from that described in this report, our recommendations should also be reviewed.
We prepared this report in substantial accordance with the generally accepted geotechnical engineering
practice as it exists in the site area at the time of our study. No warranty, either express or implied, is
made. The recommendations provided in this report are based on the assumption that an adequate
program of tests and observations will be conducted by BSK during the construction phase in order to
evaluate compliance with our recommendations. Other standards or documents referenced in any given
standard cited in this report, or otherwise relied upon by the author of this report, are only mentioned in
the given standard; they are not incorporated into it or "included by reference", as that latter term is used
relative to contracts or other matters of law.
This report may be used only by the Client and only for the purposes stated within a reasonable time from
its issuance, but in no event later than two (2) years from the date of the report, or if conditions at the
site have changed. If this report is used beyond this period, BSK should be contacted to evaluate whether
site conditions have changed since the report was issued.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 29
Also, land or facility use, on and off-site conditions, regulations, or other factors may change over time,
and additional work may be required with the passage of time. Based on the intended use of the report,
BSK may recommend that additional work be performed and that an updated report be issued.
The scope of work for this subsurface investigation and geotechnical report did not include environmental
assessments or evaluations regarding the presence or absence of wetlands at this site.
BSK conducted subsurface exploration and provided recommendations for this project. We understand
that BSK will be given the opportunity to perform a formal geotechnical review of the final project plans
and specifications. In the event BSK is not retained to review the final project plans and specifications to
evaluate if our recommendations have been properly interpreted, we will assume no responsibility for
misinterpretation of our recommendations.
We recommend that all earthwork during construction be monitored by a representative from BSK,
including site preparation, placement of engineered fill, trench backfill, and monitoring of trenchless
utility crossings. The purpose of these services would be to provide BSK the opportunity to observe the
actual soil conditions encountered during construction, evaluate the applicability of the recommendations
presented in this report to the soil conditions encountered, and recommend appropriate changes in
design or construction procedures if conditions differ from those described herein.
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California
PLATES
SITE
References: 1. http://google.com/maps, 2018
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
AS SOC I A T E S1D. Tower
6/26/18
G18/131/11L
C. Melo
VicMap.indd
Approximate Scale
Not to Scale
VICINITY MAP
New Alignment for the North Manteca Trunk Sewer
Manteca, California
W. Yo s e m i t e A v e n u e
References: 1. http://earth.google.com, 2018
Legend
Approximate Location of Current Borings
Approximate Location of Previous Borings (Year Performed)
Approximate Location of New Proposed Alignment
B-1
B-9
B-10
B-11
B-12 B-13
B-3 (2016)
B-1
B-7 (2016)
B-8 (2016)
B-1 (2015)
B-3 (2015)
B-4 (2015)
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
Reference: Geologic Map of California, San Francisco-San Jose quadrangles, 1991
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
AS SOC I A T E S
GEOLOGIC MAP
3New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
6/26/18
G18-131-11L
Approximate Scale
Not to Scale
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
AS SOC I A T E S
20
10
0
-10
Silty Sand (SM)
Poorly Graded Sand (SP)/ Poorly Graded Sand with Silt (SP-SM)
Poorly Graded Sand (SP)/ Poorly Graded Sand with Silt (SP-SM)
Sandy Lean Clay (CL)
B-10 B-9
?
Notes & References
? ?
?
? ??
?
? ?
?
Swanson Road
B-10B-9
We
st
Yo
se
mit
e A
ve
nu
e
Silty Sand (SM)Sandy Lean Clay (CL)
?
Poorly Graded Sand (SP)
SOIL PROFILE AT WEST YOSEMITE AVENUE
4New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
7/19/18
G18-131-11L
?
????
?
????
P
(
S
d?
(
d
C
S
M
S
B-1
?
Legend
????
1 -
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California
APPENDIX A
BORING LOGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
UNIFIED SOIL CLASSIFICATIONSYSTEM (ASTM D 2487/2488)
A-1D. Tower
C. Melo
Legend.indd
7/23/18
G18-131-11L
New Alignment for the North Manteca Truck Sewer
Manteca, California
Date:
File Name:
Checked By:
Project Number:
>
_
GRAVELSWITH >12%
FINES
SANDS WITH5 to 12% FINES
WELL-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE OR NO FINES
INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS
INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINESAND OR SILT
POORLY-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE FINES
WELL-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE CLAY FINES
GP
GM
(Liquid limit greater than 50)
GW-GMGW-GC
GP-GM
CLEAN GRAVELS
(More than halfof material
is smaller than
(More than halfof material
is larger thanthe #200 sieve)
COARSEGRAINED
MAJOR DIVISIONSTYPICAL
DESCRIPTIONS
SILTS AND CLAYSINORGANIC CLAYS-SILTS OF LOW PLASTICITY, GRAVELLYCLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS
GC-GM
CL-ML
OL
SOILS
SANDS
GW
GC
< _<Cu 4 and1 Cc 3
>
<>
<
GP-GC
SW
>12% FINES
SP
ML
CL
SILTS AND CLAYS
coarse fraction is smaller thanthe #4 sieve)
WITH <5%FINES
GRAVELSWITH 5 to 12%
FINES
Cu 4 and1 Cc 3
__ _<
>
<> >
Cu 4 and/or1 Cc 3
<>
CLEAN SANDS
(More than half of
is larger thanthe #4 sieve)
<> >
ORGANIC CLAYS & ORGANIC SILTS OF MEDIUM-TO-HIGHPLASTICITY
POORLY-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE CLAY FINES
OH
CHthe #200 sieve)
GRAINEDSOILS
ORGANIC SILTS & ORGANIC SILTY CLAYS OF LOWPLASTICITY
WELL-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE FINES
MH
POORLY-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE OR NO FINES
SILTY SANDS, SAND-GRAVEL-SILT MIXTURES
CLAYEY SANDS, SAND-GRAVEL-CLAY MIXTURES
CLAYEY SANDS, SAND-SILT-CLAY MIXTURES
INORGANIC SILTS AND VERY FINE SANDS, SILTY ORCLAYEY FINE SANDS, SILTS WITH SLIGHT PLASTICITY,
GRAVELS
WITH <5%FINES
SANDS WITH
coarse fraction
(More than half of
FINE
Cu 6 and1 Cc 3
(Liquid limit less than 50)
POORLY-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE CLAY FINES
POORLY-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE FINES
WELL-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE CLAY FINES
Cu 6 and/or1 Cc 3
WELL-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE FINES
POORLY-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE OR NO FINES
SILTY GRAVELS, GRAVEL-SILT-SAND MIXTURES
CLAYEY GRAVELS, GRAVEL-SAND-CLAY MIXTURES
Cu 6 and1 Cc 3
Cu 6 and/or1 Cc 3
<
SW-SM
SW-SC
SP-SMSP-SC
SMSC
SC-SM
GRAPHICLOG
<_
_ _
>Cu 4 and/or1 Cc 3
<
CLAYEY GRAVELS, GRAVEL-SAND-CLAY-SILTMIXTURES
WELL-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE OR NO FINES
__
__
>
<>
INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY,GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEANCLAYS
UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM D 2487/2488)
UNIFIED SOIL CLASSIFICATIONSYSTEM (ASTM D 2487/2488)
Entry By:
Exhibit
B-1AT&T DATA CENTERPLANNED BLOOM ENERGY FUELS CELLS
2525 N. WATNEY WAYFAIRFIELD, CALIFORNIA
09/24/13
B. Steen
blogsC. Foulk
G13-161-10P
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E SA-2
SOIL DESCRIPTION KEY
D. Tower
C. Melo
Legend.indd
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G18-131-11L
New Alignment for the North Manteca Truck Sewer
Manteca, California
Date:
File Name:
Checked By:
Project Number:
Very HardThe thread cannot be rerolled after reaching
Thumb will indent soil about 1/4 in. (6 mm)
Cohesive soil that can be broken down into small angularlumps which resist further breakdown
#10 - #4 Rock salt-sized to pea-sized#40 - #10 0.017 - 0.079" Sugar-sized to rock salt-sized
Flour-sized to sugar-sized
Weak
CRITERIA
High (H)
SR
Boulders
of sand scattered through a mass of clay; note thickness
DESCRIPTION
Inclusion of small pockets of different soils, such as small lenses
It takes considerable time rolling and kneeding
Same color and appearance throughout
Thumb will penetrate soil more than 1 in. (25 mm)
Thumb will penetrate soil about 1 in. (25 mm)
Thumb wil not indent soil but readily indented with thumbnail
Thumbnail will not indent soil
DESCRIPTION
Stratified
Laminated
Fissured
Slickensided
plastic limit.
Blocky
Lensed
Homogeneous
Strong
SA
A
ABBR
(# blows/ft)
Pea-sized to thumb-sized
the plastic limit. The lump or thread crumbles
limit. The lump or thread can be formed without
medium
Gravel
Particles are similar to angular description but have
Sand
Fines
coarse
fine
Passing #200
Thumb-sized to fist-sized
DESCRIPTION
DESCRIPTION
fine #200 - #10
ABBR
Angular
3/4 -3"
HP
MP
LP
NP
>12"
3/4 -3"
FIELD TESTFIELD TEST
Alternating layers of varying material or color with layersat least 1/4 in. thick, note thickness
to reach the plastic limit. The thread can bererolled several times after reaching the plastic
crumbling when drier than the plastic limit
DESCRIPTIONNone
Larger than basketball-sizedFist-sized to basketball-sized
Flour-sized and smaller<0.0029
Crumbles or breaks with considerable
CALIFORNIA
CRITERIA
Medium (M)
Subangular
LooseVery Loose
DENSITY
Rounded
Alternating layers of varying material or color with the layer
Rounded
LVL
Crumbles or breaks with handling or slight
Fracture planes appear polished or glossy, sometimes striated
Breaks along definite planes of fracture with little resistanceto fracturing
SIZE>12"
3 - 12' 3 - 12"
#4 - 3/4"
DESCRIPTION
Low (L) SF
VH
H
FIELD TEST
FIELD TEST
is required to reach the plastic limit.
<55 - 1515 - 4040 - 70
>70 85 - 10065 - 85
ABBR
Very DenseDense
Medium Dense
0.19 - 0.75"
Cobbles
SIEVESIZE
GRAINSIZE
APPROXIMATE
Particles have nearly plane sides but havewell-rounded corners and edges
Angular
Subangular
Subrounded
SOIL DESCRIPTION KEY
Particles have sharp edges and relatively planesides with unpolished surfaces
0.0029 - 0.017"
rounded edges
Damp but no visible waterVisible free water, usually soil is below water table
finger pressure
finger pressure
Will not crumble or break with finger pressure
DESCRIPTION
APPARENT
35 - 6515 - 350 - 15(%)
RELATIVEDENSITYSAMPLER
CONSISTENCY
Very SoftSoftFirmHard
Subrounded
VDD
MD
SPT(# blows/ft)
<44 - 1010 - 3030 - 50
>50
Particles have smoothly curved sides and no edges
No visible reactionSome reaction, with bubbles forming slowlyViolent reaction, with bubbles forming immediately
ABBR FIELD TEST
DryMoistWet
DMW
Non-plastic
coarse 0.079 - 0.19"
R
A 1/8-in. (3 mm) thread cannot be rolled at
The thread is easy to roll and not much time
Absence of moisture, dusty, dry to the touch
or thread cannot be formed when drier than the
any water content.The thread can barely be rolled and the lump
Weakly
Moderately
Strongly
ABBR
VS
less than 1/4 in. thick, note thickness
when drier than the plastic limit
Penetrated only a few inches with 1/2-inch reinforcing rod driven with 5-lb. hammerDifficult to penetrate a foot with 1/2-inch reinforcing rod driven with 5-lb. hammer
Difficult to penetrate with 1/2-inch reinforcing rod pushed by handEasily penetrated a foot with 1/2-inch reinforcing rod driven with 5-lb. hammer
Easily penetrated with 1/2-inch reinforcing rod by hand
SOIL DESCRIPTION KEY
FIELD TEST
>6035 - 6012- 355 - 12
<4(# blows/ft)SAMPLER
MODIFIED CA
Entry By:
Exhibit
GRAIN SIZE REACTION WITH HCL
CONSISTENCY - FINE-GRAINED SOIL
STRUCTURE
ANGULARITY
APPARENT / RELATIVE DENSITY - COARSE-GRAINED SOIL
MOISTURE CONTENT
CEMENTATION
PLASTICITY
B-2AT&T DATA CENTERPLANNED BLOOM ENERGY FUELS CELLS
2525 N. WATNEY WAYFAIRFIELD, CALIFORNIA
09/24/13
B. Steen
blogs
C. Foulk
G13-161-10P
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E SA-3
LOG KEY
D. Tower
C. Melo
Legend.indd
7/23/18
G18-131-11L
New Alignment for the North Manteca Truck Sewer
Manteca, California
Date:
File Name:
Checked By:
Project Number:LOG KEY
GENERAL NOTES
ROCK CORE
LOG SYMBOLS
SEEPAGE
PI
CONTINUOUS CORE
-4
MC MOISTURE CONTENT(ASTM Test Method D 2216)
BULK / BAG SAMPLE
LIQUID LIMIT(ASTM Test Method D 4318)LL
PERCENT FINERTHAN THE NO. 200 SIEVE(ASTM Test Method C 117)
-200
SHELBY TUBE
UNCONFINED COMPRESSION(ASTM Test Method D 2166)UC
EXPANSION INDEX(UBC STANDARD 18-2)
TXUUUNCONSOLIDATED UNDRAINEDTRIAXIAL COMPRESSION(EM 1110-1-1906)/ASTM TestMethod D 2850
GROUNDWATER LEVEL(encountered at time of drilling)
COLLAPSE POTENTIALCOL
Boring log data represents a data snapshot.
This data represents subsurface characteristics only to the extent encountered at the location of the boring.
The data inherently cannot accurately predict the entire subsurface conditions to be encountered at the project site relative toconstruction or other subsurface activities.
Lines between soil layers and/or rock units are approximate and may be gradual transitions.
The information provided should be used only for the purposes intended as described in the accompanying documents.
In general, Unified Soil Classification System designations presented on the logs were evaluated by visual methods.
Where laboratory tests were performed, the designations reflect the laboratory test results.
EI
PLASTICITY INDEX(ASTM Test Method D 4318)
PERCENT FINERTHAN THE NO. 4 SIEVE(ASTM Test Method C 136)
STANDARD PENETRATIONSPLIT SPOON SAMPLER(2 inch outside diameter)
SPLIT BARREL SAMPLER(3 inch outside diameter)
SPLIT BARREL SAMPLER(2-1/2 inch outside diameter)
GROUNDWATER LEVEL(measured after drilling)
Entry By:
Exhibit
B-3AT&T DATA CENTERPLANNED BLOOM ENERGY FUELS CELLS
2525 N. WATNEY WAYFAIRFIELD, CALIFORNIA
09/24/13
B. Steen
blogs
C. Foulk
G13-161-10P
107
100
1A1B1C
2A2B2C
3
4
5A5B5C
43
4
19
Silty Sand (SM): olive brown, moist, dense, fine to mediumgrained sand, decreasing silt content with depth, iron oxidestaining
Poorly Graded Sand with Silt (SP-SM): olive brown, moist,medium dense, fine to medium grained sand
Silty Sand (SM): olive brown, moist, medium dense, fine tomedium grained sand
olive brown mottled with light brownish gray
yellowish brown, fine to coarse grained sand
light brownish gray mottled with olive brown, increased siltcontent, fine to medium grained sand
Poorly Graded Sand (SP): light brownish gray, wet,medium dense, fine to coarse grained sand
New Alignment North Manteca Trunk SewerG18-131-11LManteca, CaliforniaD. TowerM. Romero
MATERIAL DESCRIPTION
Sam
ple
s
Pen
etra
tion
Blo
ws
/ 6 in
ches
BSK Associates399 Lindbergh AvenueLivermore, CA 94551Telephone: (925)-315-3151Fax: (925)-315-3152
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18
112
83
90
1A1B1C
2
3A3B3C
4
5A5B5C
1.5
29
3
6
22
33
ASPHALT: approximately 1.5 inches of asphaltAGGREGATE BASE: approximately 2 inches of gravel,possibly aggregate baserock (FILL)Silty Sand (SM): yellowish brown, moist, loose, fine tomedium grained sand, iron oxide staining
medium dense, clay seamDirect Shear (see Plate B-4)
Poorly Graded Sand (SP): brown, moist, medium dense,fine to coarse grained sand
Lean Clay with Sand (CL): olive brown, wet, firm, mediumplasticity, fine to medium grained sand, high silt content
seam of poorly graded sandTXUU (see plate B-1) c= 1,490 psf
New Alignment North Manteca Trunk SewerG18-131-11LManteca, CaliforniaD. TowerM. Romero
MATERIAL DESCRIPTION
Sam
ple
s
Pen
etra
tion
Blo
ws
/ 6 in
ches
BSK Associates399 Lindbergh AvenueLivermore, CA 94551Telephone: (925)-315-3151Fax: (925)-315-3152
GE
O_T
AR
GE
T N
EW
ALI
GN
ME
NT
BO
RIN
G L
OG
S.G
PJ
GE
OT
EC
HN
ICA
L 08
.GD
T 7
/24/
18
105
101
1
2A2B2C
3
4A4B4C
5
13
2
8
14
ASPHALT: approximately 1 inch of asphaltAGGREAGTE BASE: approximately 3 inches of gravel,possibly aggregate base (FILL)Silty Sand (SM): dark reddish brown, moist, loose, fine tomedium grained sand
R-Value= 59 (see Plate B-11)
brown, fine to coarse grained sand
Poorly Graded Sand with Silt (SP-SM): brown, moist,medium dense, fine to medium grained sand, iron oxidestaining
Poorly Graded Sand (SP): light brownish gray, very moist,medium dense, fine to medium grained sand
New Alignment North Manteca Trunk SewerG18-131-11LManteca, CaliforniaD. TowerM. Romero
MATERIAL DESCRIPTION
Sam
ple
s
Pen
etra
tion
Blo
ws
/ 6 in
ches
BSK Associates399 Lindbergh AvenueLivermore, CA 94551Telephone: (925)-315-3151Fax: (925)-315-3152
GE
O_T
AR
GE
T N
EW
ALI
GN
ME
NT
BO
RIN
G L
OG
S.G
PJ
GE
OT
EC
HN
ICA
L 08
.GD
T 7
/24/
18
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California
APPENDIX B
LABORATORY TEST RESULTS
0
LIQUID LIMIT (LL)
50
30
Inorganic clayey silts to veryfine sands of slight plasticity
10 100
UNIFIED SOIL CLASSIFICATIONFINE GRAINED SOIL GROUPS
20
Inorganic clays ofhigh plasticity
Inorganic clays of lowto moderate plasticity
Inorganic silts andclayey silts
EXPL
AN
ATI
ON
20
20
Dark Brownish Gray Silt with Sand (ML)
PLASTICITY CHART
C-1
26B-13 11
60
PI
Organic clays of moderate to highplasticity, organic silts
40
or
0
PLA
STIC
ITY
IND
EX (P
I)
80
Organic silts and organic siltyclays of low plasticity
100
50
DEPTH (ft)
40
7060
30
80
30
DESCRIPTION
60 7050
GROUPSYMBOL
LL PLLEGEND:
or
10 10
A-LINEU-LINE
90
90
14.0 37
SOURCE
1 of 1
PlateDate: 07-16-13
Entry By: J. Sala
File Name: 134350 blogs
Checked By: B. Steen
Project Number: 134350
SOUTHLAND MALLHEALTH CLUB
HAYWARD, CALIFORNIA
KA_
ATT
ER
BER
G
KA
CO
RPO
RAT
E S
TD.G
DT
KA
CO
RPO
RAT
E S
TD -
0920
11.G
LB
1343
50 B
LOG
S.G
PJ
7/1
7/13
CL
MH OH
OL
OH
MH
ML-CL ML
CH
CH
OL
ML
CL
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
Note: Strengths are picked at the peak deviator stress or 15% strain which ever occurs first per ASTM D2850.
Remarks:
Sample Data
Visual Soil Description
Lean Clay with Sand (CL)Silt with Sand (ML)
664-204BSK AssociatesG18-131-11L
0.0
2.0
4.0
0.0 2.0 4.0 6.0 8.0
Shea
r Str
ess,
ksf
Total Normal Stress, ksf
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
0.0 6.0 12.0 18.0 24.0
Dev
iato
r Str
ess,
ksf
Strain, %
Stress-Strain CurvesSample 1
Sample 2
Sample 3
Sample 4
Unconsolidated-Undrained Triaxial TestASTM D2850
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
BSK AssociatesNew Alignment North Manteca Sewer Tank
664-204 G18-131-11L7/12/2018
*DS-CU* A fully undrained condition may not be attained in this test. ΔH is not measured during undrained direct shear tests.
Light Brownish Gray Poorly
Graded Sand
Visual Description:
Light Brownish Gray Poorly
Graded Sand
Light Brownish Gray Poorly
Graded Sand
Remarks:
604
Specimen Data
Cohesion (psf) Ult. Cohesion (psf)
0
1000
2000
3000
4000
5000
6000
0.0 5.0 10.0 15.0 20.0 25.0
Shea
r Str
ess
(psf
)
Deformation (%)
Shear Stress vs. DeformationSample 1
Sample 2
Sample 3
Sample 4
0
2000
4000
6000
8000
0 2000 4000 6000 8000
Shea
r Str
ess,
psf
Normal Load, psf
Shear Stress vs. Normal LoadPeakShear StressUlt. StressUltimate
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.20000.0 5.0 10.0 15.0 20.0 25.0
Del
ta h
(in)
Deformation (%)
Change in Height
Sample 1
Sample 2
Sample 3
Sample 4
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
*DS-CU* A fully undrained condition may not be attained in this test. ΔH is not measured during undrained direct shear tests.
YellowishBrown Silty
SAND
Visual Description:
YellowishBrown Silty
SAND
YellowishBrown Silty
SAND
Remarks:
Consolidated Undrained Direct Shear(ASTM D3080M)
BSK AssociatesNew Alignment Manteca Sewer Tank
664-204 G18-131-11L7/13/2018
0
500
1000
1500
2000
2500
3000
3500
0.0 5.0 10.0 15.0 20.0 25.0
Shea
r Str
ess
(psf
)
Deformation (%)
Shear Stress vs. DeformationSample 1
Sample 2
Sample 3
Sample 4
0
2000
4000
6000
8000
0 2000 4000 6000 8000
Shea
r Str
ess,
psf
Normal Load, psf
Shear Stress vs. Normal LoadPeakShear StressUlt. StressUltimate
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.20000.0 5.0 10.0 15.0 20.0 25.0
Del
ta h
(in)
Deformation (%)
Change in Height
Sample 1
Sample 2
Sample 3
Sample 4
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
BSK AssociatesNew Alignment Northh Manteca Sewer Tank
664-204 G18-131-11L7/13/2018
*DS-CU* A fully undrained condition may not be attained in this test. ΔH is not measured during undrained direct shear tests.
Light Brownish Gray Poorly
Graded Sand
Visual Description:
Light Brownish Gray Poorly
Graded Sand
Light Brownish Gray Poorly
Graded Sand
Remarks:
1100
Specimen Data
Cohesion (psf) Ult. Cohesion (psf)
0
1000
2000
3000
4000
5000
6000
0.0 5.0 10.0 15.0 20.0 25.0
Shea
r Str
ess
(psf
)
Deformation (%)
Shear Stress vs. DeformationSample 1
Sample 2
Sample 3
Sample 4
0
2000
4000
6000
8000
0 2000 4000 6000 8000
Shea
r Str
ess,
psf
Normal Load, psf
Shear Stress vs. Normal LoadPeakShear StressUlt. StressUltimate
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.20000.0 5.0 10.0 15.0 20.0 25.0
Del
ta h
(in)
Deformation (%)
Change in Height
Sample 1
Sample 2
Sample 3
Sample 4
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
CONSOLIDATED UNDRAINED DIRECT SHEAR
B-5New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
7/19/18
G18-131-11L
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Coarse Medium Fine
- 3 67 27
Description of Soil: Poorly Graded Sand (SP)
Silt (non-plastic) and Clay (plastic)
3
CG L18-482
399 Lindbergh AveLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
GRAIN SIZE ANALYSIS OF SOILS(ASTM D 422)
NV5 G18-131-11LNew Alignment North Manteca B-10
RC
0
7/9/2018
PARTICLE SIZE DISTRIBUTION
Cobbles
Gravel Sand
13.5-15
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.001
0.01
0.1
110100
Perc
ent P
assi
ng, %
Particle Size, mm3
-in #4
#10
#40
#200
60-min
0.005
0.074
0.425
2.00
4.76
76.2
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
GRAIN SIZE ANALYSIS OF SOILSASTM D422
B-6New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
7/19/18
G18-131-11L
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Coarse Medium Fine
- 0 19 75
Description of Soil: Poorly Graded Sand with Silt (SP-SM)
RC
0
7/9/2018
PARTICLE SIZE DISTRIBUTION
Cobbles
Gravel Sand
23.5'-25'
Silt (non-plastic) and Clay (plastic)
6
CG SPT#6
399 Lindbergh AveLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
GRAIN SIZE ANALYSIS OF SOILS(ASTM D 422)
NV5 G18-131-11LNew Alignment North Manteca B-10
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.001
0.01
0.1
110100
Perc
ent P
assi
ng, %
Particle Size, mm3
-in #4
#10
#40
#200
60-min
0.005
0.074
0.425
2.00
4.76
76.2
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
GRAIN SIZE ANALYSIS OF SOILSASTM D422
B-7New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
7/19/18
G18-131-11L
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Coarse Medium Fine
- 2 59 37
Description of Soil: Poorly Graded Sand (SP)
Silt (non-plastic) and Clay (plastic)
2
CG SPT#5
399 Lindbergh AveLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
GRAIN SIZE ANALYSIS OF SOILS(ASTM D 422)
NV5 G18-131-11LNew Alignment North Manteca B-11
RC
0
7/9/2018
PARTICLE SIZE DISTRIBUTION
Cobbles
Gravel Sand
18.5-20
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.001
0.01
0.1
110100
Perc
ent P
assi
ng, %
Particle Size, mm3
-in #4
#10
#40
#200
60-min
0.005
0.074
0.425
2.00
4.76
76.2
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
GRAIN SIZE ANALYSIS OF SOILSASTM D422
B-8New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
7/19/18
G18-131-11L
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Coarse Medium Fine
- 1 52 45
Description of Soil: Poorly Graded Sand (SP)
Silt (non-plastic) and Clay (plastic)
2
RC
0
7/9/2018
PARTICLE SIZE DISTRIBUTION
Cobbles
Gravel Sand
9.5'CG L18-482
399 Lindbergh AveLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
GRAIN SIZE ANALYSIS OF SOILS(ASTM D 422)
NV5 G18-131-11LNew Alignment North Manteca B-12
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.001
0.01
0.1
110100
Perc
ent P
assi
ng, %
Particle Size, mm3
-in #4
#10
#40
#200
60-min
0.005
0.074
0.425
2.00
4.76
76.2
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
GRAIN SIZE ANALYSIS OF SOILSASTM D422
B-9New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
7/19/18
G18-131-11L
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Coarse Medium Fine
- 1 48 48
Description of Soil: Poorly Graded Sand (SP)
Silt (non-plastic) and Clay (plastic)
3
CG SPT#5
399 Lindbergh AveLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
GRAIN SIZE ANALYSIS OF SOILS(ASTM D 422)
NV5 G18-131-11LNew Alignment North Manteca B-13
RC
0
7/6/2018
PARTICLE SIZE DISTRIBUTION
Cobbles
Gravel Sand
18.5'-20'
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.001
0.01
0.1
110100
Perc
ent P
assi
ng, %
Particle Size, mm3
-in #4
#10
#40
#200
60-min
0.005
0.074
0.425
2.00
4.76
76.2
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
GRAIN SIZE ANALYSIS OF SOILSASTM D422
B-10New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
7/19/18
G18-131-11L
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Coarse Medium Fine
- 1 48 48
Description of Soil: Poorly Graded Sand (SP)
Silt (non-plastic) and Clay (plastic)
3
CG SPT#5
399 Lindbergh AveLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
GRAIN SIZE ANALYSIS OF SOILS(ASTM D 422)
NV5 G18-131-11LNew Alignment North Manteca B-13
RC
0
7/6/2018
PARTICLE SIZE DISTRIBUTION
Cobbles
Gravel Sand
18.5'-20'
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.001
0.01
0.1
110100
Perc
ent P
assi
ng, %
Particle Size, mm
3-in #4
#10
#40
#200
60-min
0.005
0.074
0.425
2.00
4.76
76.2
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
399 Lindbergh AveLivermore, CA 94551
Ph: (925) 315-3151Fax: (925) 315-3152
Sample Date: 6/21/2018Sample By: DT
Test Date: 7/9/2018Report Date: 7/10/2018
Tested By: RC
SPECIMEN A B CEXUDATION PRESSURE, LOAD (lb) 6896 4432 2570EXUDATION PRESSURE, PSI 549 353 205EXPANSION, * 0.0001 IN 0 0.0002 0.0001EXPANSION PRESSURE, PSF 0 0 0
Enter value of "T" from the Chart above STABILOMETER PH AT 2000 LBS 28 40 48DISPLACEMENT 4.17 4.73 4.23
74 61 5874 61 578.4 8.8 9.7
DRY DENSITY AT TEST, PCF 129.8 128.1 127.6
"R" VALUE BY EXPANSION
Remark:
59
N/APRESSURE TI = 4.0, GF=1.50
RESISTANCE VALUE "R"
% MOISTURE AT TEST
"R" VALUE AT 300 PSI EXUDATION PRESSURE
"R" VALUE CORRECTED FOR HEIGHT
R-Value Test
Caltrans Test Method 301
Sample Description: Dark Reddish Brown Silty Sand (SM)
New AlignmentG18-131-11L
L18-482B-11@1-5
Project Name:Project Number:
Lab Tracking ID:Sample Location:
Sample Source:
COVER THICKNESS BY EXPANSION PRESSURE, INCHES
"R" V
ALU
E
CO
VE
R T
HIC
KN
ES
S B
Y S
TAB
ILO
ME
TER
, IN
CH
ES
EXUDATION PRESSURE, PSI
0 2 4 6 8 10 12 14 16 18 20 22 24 26
100
90
80
70
60
50
40
30
20
10
0
0
2
4
6
8
10
12
14
16
18
20
22
2410020300400500600700800 0
Reviewed By: ____JKA_______
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
R- VALUE TEST
B-11New Alignment for the
North Manteca Trunk SewerManteca, California
D. Tower
C. Melo
SitePlan.indd
7/19/18
G18-131-11L
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California
APPENDIX C
SUBSURFACE DATA FROM PREVIOUS INVESTIGATIONS
• BSK (2018), Geotechnical Investigation Report, North Manteca Trunk Sewer and Milo Candini
Drive Extension, 1215 West Center Street, Suite 201, Manteca, California, dated June 29, 2018
(File No. G16-127-11L)
• BSK (2016), Geotechnical Investigation Report, Manteca Water Quality Control Facility
Improvements, 2450 West Yosemite Avenue, Manteca, California, dated May 6, 2016 (File No.
G15-133-10L)
111
83
91114
479
101213
101518
6813
1A1B1C
2
3A3B3C
4
5A5B5C
3-3.5
3-3.5
3
5
37
GRAVEL : fillPOORLY GRADED SAND WITH SILT (SP-SM) : olive brown, slightly moist, fine grained sand (FILL)
POORLY GRADED SAND WITH SILT (SP-SM):olive to olive brown, moist, medium dense, fine to mediumgrained sand
pocket of well graded sand, fine to medium grained sand
POORLY GRADED SAND (SP): olive brown, moist, medium dense, fine to medium grainedsand
Manteca Water Quality Control FacilityG15-133-10LManteca, CaliforniaK. JohnstonC. Melo
BSK Associates324 Earhart WayLivermore, CA 94551Telephone: 925-315-3151Fax: 925-315-3152
MATERIAL DESCRIPTION
Sam
ples
GE
O_T
AR
GE
T G
15-1
33-1
0L M
AN
TE
CA
WW
TP
.GP
J G
EO
TE
CH
NIC
AL
08.G
DT
1/6
/16
104
103
1088
446
467
4910
71717
1A1B1C
2A2B2C
3A3B3C
4A4B4C
5A5B5C 2.0-3.0
8
9
18
GRAVEL: fillPOORLY GRADED SAND WITH SILT (SP-SM)):olive to olive brown, slightly moist, fine grained sand, micaspecs (FILL)POORLY GRADED SAND WITH SILT (SP-SM):olive to olive brown, slightly moist, medium dense, finegrained sand, mica specs
loose
POORLY GRADED SAND (SP):gray to olive gray, moist, loose, fine to medium grained sand
11:49 am
11:34 am
wet, medium dense
LEAN CLAY (CL):light brownish gray, moist, firm, low to medium plasticity,mica specsBoring terminated at approximately 21.5 feet.Boring backfilled with cement grout.
Exploration Geoservices Inc., Mobile B-538.25-inch metal carbine combo, hollow stem auger140 lb8-inches30 inSurface Conditions: Gravel access road
21.57/30/157/30/152.5 inch inner diameter1.4 inch inner diameter
North Manteca Trunk SewerG16-127-11LManteca, CAD. TowerM. McNally
MATERIAL DESCRIPTION
Sam
ples
Pen
etra
tion
Blo
ws
/ 6
inch
es
BSK Associates324 Earhart WayLivermore, CA 94551Telephone: (925)-315-3151Fax: (925)-315-3152
GE
O_T
AR
GE
T B
OR
ING
LO
GS
.GP
J G
EO
TE
CH
NIC
AL
08.G
DT
11/
9/1
6
6
7
8A8B8C
9
POORLY GRADED SAND WITH SILT (SP-SM): brown,wet, medium dense, fine to coarse grained sand
SANDY LEAN CLAY (CL): light brownish gray, wet, firm,fine grained sandPOORLY GRADED SAND WITH SILT (SP-SM): brown,wet, medium dense, fine to coarse grained sand
SANDY FAT CLAY (CH): dark brownish gray, moist to wet,firm, medium to high plasticity, fine to coarse grained sand
CLAYEY SAND (SC): light brownish gray, wet, loose tomedium dense, fine to medium grained sand, iron oxidestaining
POORLY GRADED SAND (SP): multicolored, wet,medium dense, fine to coarse grained sand
Boring terminated at approximately 40 feet. Freegroundwater first observed at approximately 12.5 feet andthen remeasured at approximately 21.5 feet. Boring wasbackfilled with cement grout and patched with approximately6 inches of Quickrete.
*DS-CU* A fully undrained condition may not be attained in this test. ΔH is not measured during undrained direct shear tests.
Brown SiltySAND
Visual Description:
Brown SiltySAND
Brown SiltySAND
Remarks:
Consolidated Undrained Direct Shear(ASTM D3080M)
BSK AssociatesN.Manteca Sewer Trunk
664-092 G16-127-11L10/27/2016
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0.0 5.0 10.0 15.0 20.0 25.0Sh
ear S
tres
s (p
sf)
Deformation (%)
Shear Stress vs. Deformation
Sample 1
Sample 2
Sample 3
0
2000
4000
6000
8000
0 2000 4000 6000 8000
Shea
r Str
ess,
psf
Normal Load, psf
Shear Stress vs. Normal LoadPeakShear StressUlt. StressUltimate
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.20000.0 5.0 10.0 15.0 20.0 25.0
Del
ta h
(in)
Deformation (%)
Change in Height
Sample 1
Sample 2
Sample 3
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
DIRECT SHEAR RESULTS
B-1North Manteca Trunk Sewer
Manteca, California
D. Tower
10/31/16
G16-127-11L
C. Melo
SitePlan.indd
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
*DS-CU* A fully undrained condition may not be attained in this test. ΔH is not measured during undrained direct shear tests.
Gray Poorly Graded Sand
Visual Description:
Gray Poorly Graded Sand
Gray Poorly Graded Sand
Remarks:
Specimen Data
Cohesion (psf) Ult. Cohesion (psf)
0
1000
2000
3000
4000
5000
6000
7000
8000
0.0 5.0 10.0 15.0 20.0 25.0
Shea
r Str
ess
(psf
)
Deformation (%)
Shear Stress vs. Deformation
Sample 1
Sample 2
Sample 3
0
2000
4000
6000
8000
0 2000 4000 6000 8000
Shea
r Str
ess,
psf
Normal Load, psf
Shear Stress vs. Normal LoadPeakShear StressUlt. StressUltimate
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.20000.0 5.0 10.0 15.0 20.0 25.0
Del
ta h
(in)
Deformation (%)
Change in Height
Sample 1
Sample 2
Sample 3
DIRECT SHEAR RESULTS
B-4North Manteca Trunk Sewer
Manteca, California
D. Tower
11/1/16
G16-127-11L
C. Melo
SitePlan.indd
Ø>40º, Assume Ø=40º, C=0 psf
See NoteSee Note
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
*DS-CU* A fully undrained condition may not be attained in this test. ΔH is not measured during undrained direct shear tests.
Brown Silty Sand
Visual Description:
Brown Silty Sand
Brown Silty Sand
Remarks:
500
Specimen Data
Cohesion (psf) Ult. Cohesion (psf)
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0.0 5.0 10.0 15.0 20.0 25.0
Shea
r Str
ess
(psf
)
Deformation (%)
Shear Stress vs. Deformation
Sample 1
Sample 2
Sample 3
0
2000
4000
6000
8000
0 2000 4000 6000 8000
Shea
r Str
ess,
psf
Normal Load, psf
Shear Stress vs. Normal LoadPeakShear StressUlt. StressUltimate
0.0000
0.2000
0.4000
0.6000
0.8000
1.0000
1.20000.0 5.0 10.0 15.0 20.0 25.0
Del
ta h
(in)
Deformation (%)
Change in Height
Sample 1
Sample 2
Sample 3
DIRECT SHEAR RESULTS
B-5North Manteca Trunk Sewer
Manteca, California
D. Tower
11/1/16
G16-127-11L
C. Melo
SitePlan.indd
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Clay (Plastic)
Coarse Medium Fine
- 3 51 42 #N/A
Specific Gravity, Gs - 2.65
Description of Soil: Poorly Graded Sand (SP)
GAM / RAK SPT #05
324 Earhart WayLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
GRAIN SIZE ANALYSIS OF SOILS(ASTM D 422)
G16 - 127 - 11LNorth Manteca Trunk Sewer B - 3
#N/A
11/4/2016
PARTICLE SIZE DISTRIBUTIONC
obbles
Gravel Sand Silt (non-plastic)
18.5' - 20.0'
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
0.001
0.01
0.1
110100
Perc
ent P
assi
ng, %
Particle Size, mm
3 -in #4
#10
#40
#200
60-min
0.005
0.074
0.425
2.00
4.76
76.2
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
SIEVE ANALYSIS
B-7North Manteca Trunk Sewer
Manteca, California
D. Tower
10/31/16
G16-127-11L
C. Melo
SitePlan.indd
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Clay (Plastic)
Coarse Medium Fine
- 0 39 52 #N/A
Specific Gravity, Gs - 2.65
Description of Soil: Poorly Graded Sand with Silt (SP-SM)
#N/A
11/4/2016
PARTICLE SIZE DISTRIBUTIONC
obbles
Gravel Sand Silt (non-plastic)
8.5' - 10.0'GAM / RAK SPT #03
324 Earhart WayLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
SIEVE ANALYSIS
B-11North Manteca Trunk Sewer
Manteca, California
D. Tower
10/31/16
G16-127-11L
C. Melo
SitePlan.indd
Client: Project No.:Project: Boring Number:
Tested By: Sample ID:Reviewed By: Sample Depth:
Date Tested:
Clay (Plastic)
Coarse Medium Fine
- 2 23 67 #N/A
Specific Gravity, Gs - 2.65
Description of Soil: Poorly Graded Sand with Silt (SP-SM)
GAM / RAK SPT #05
324 Earhart WayLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152
HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS
The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.
A S S O C I A T E S
SIEVE ANALYSIS
B-12North Manteca Trunk Sewer
Manteca, California
D. Tower
10/31/16
G16-127-11L
C. Melo
SitePlan.indd
Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California
APPENDIX D
SUMMARY OF COMPACTION RECOMMENDATIONS
Area Compaction Recommendations (See Notes 1, 2, 3, 4)
Subgrade Preparation and Placement of General Engineered Fill, Including Imported Fill
Compact upper 12 inches of subgrade and entire depth of fill to a minimum of 90 percent compaction at near optimum moisture content for granular soils and to a minimum of 90 percent compaction at a minimum of 2 percent over optimum moisture content for clayey soils.
Trenches and Excavations5, 6 Compact trench backfill to a minimum of 90 percent compaction at near optimum moisture content for granular soils and to a minimum of 90 percent compaction at a minimum of 2 percent over optimum moisture content for clayey soils. Proper granular bedding and shading should be used beneath and around new utilities. Where trenches will be under pavements, the upper 12 inches should be compacted as recommended below.
Pavements Compact upper 12 inches of subgrade to at least 95 percent
compaction at near optimum moisture content for granular soils and to at least 93 percent compaction at least 2 percent over optimum moisture content for clayey soils. Compact aggregate base to at least 95 percent compaction at near optimum moisture content.
Notes:
(1) Depths are below finished subgrade elevation. (2) All compaction requirements refer to relative compaction as a percentage of the laboratory standard
described by ASTM D 1557.
(3) Fill material should be compacted in lifts not exceeding 8 inches in loose thickness.
(4) All subgrades should be firm and stable.
(5) In landscaping areas only, the percent compaction in excavations may be reduced to 85 percent.
(6) Where backfills are greater than 7 feet in depth below finish grade, the portion below a depth of 7 feet should be compacted to a minimum of 95 percent compaction where new or existing surface improvements are located within a 1H:1V projection line extending up from the bottom of trench excavations.