FACULTY : CIVIL & ENVIRONMENTAL ENGINEERING NO. OF PAGES: 1/5 DEPARTMENT : GEOTECHNICAL & TRANSPORTATION ENGINEERING EDITION: LAB 4a NO. OF CHECKING: LABORATORY : ENGINEERING GEOLOGY & GEOPHYSIC LABORATORY EFECTIVE DATE : 8/1/2007 TOPIC : PLOTTING POLES AND CONTOURING OF STRUCTURAL GEOLOGY DATA ( LAB 4a ) AMENDMENT DATE: 8/1/2007 1.0 OBJECTIVE To plot poles and carry out contouring of the structural geology data. 2.0 LEARNING OUTCOMES a) Students should able to use the geological compass. b) Students should able to measures the dip and dip direction of any planes. c) Students should able to plot poles of the structural geology data. d) Students should able to plot contour from the structural geology data. 3.0 THEORY Analysis of the orientation of structural geology data involves; Plotting poles representing the dip and dip direction of each discontinuity. This plot will help to identify discontinuity sets, for which both the average orientation and the scatter (dispersion) can be calculated. The second step in the analysis is to plot great circles representing the average orientation of each set, major discontinuities such as faults, and the dip and dip direction of the cut face. 4.0 EQUIMENT AND MATERIALS Equal-area for plotting poles and great circles (Appendix C) Equal-area polar net (Appendix D) Kalsbeek counting net (Appendix E) Tracing paper Pencil 5.0 PROCEDURE Poles can be plotted on the polar stereonet on which the dip direction is indicated on the periphery of the circle, and the dip is measured along radial lines with zero degrees at the center. The procedure for plotting poles is to lay a sheet of tracing paper on the printed polar net and mark the north direction and each quadrant position around the edge of the outer circle. A mark is then made to show the pole that represents the orientation of each discontinuity as defined by its dip and dip direction. Poles for shallow dipping discontinuities lie close to the center of the circle, and poles of steeply dipping discontinuities lie close to the periphery of the circle. Concentrations of pole orientations can be identified using Kalsbeek counting net. The Kalsbeek net is made up of mutually overlapping hexagons, each with an area of 1/100 of the full area of the stereonet. Contouring is performed by overlaying the counting net on the pole and counting the number of poles in each hexagon; this number is marked on the net. These numbers of poles are converted into percentages by dividing each by the total number of poles and multiplying by 100. Once a percentage is written in each hexagon, contours can be developed by interpolation. Prepared by : Lecturer Name : Aziman Bin Madun / Mohd Hazreek Bin Zainal Abidin Signature : Date : 8 January 2007
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FACULTY : CIVIL & ENVIRONMENTAL ENGINEERING NO. OF PAGES: 1/5
DEPARTMENT : GEOTECHNICAL & TRANSPORTATION ENGINEERING
TOPIC : PLOTTING POLES AND CONTOURING OF STRUCTURAL GEOLOGY DATA ( LAB 4a )
AMENDMENT DATE: 8/1/2007
1.0 OBJECTIVE
To plot poles and carry out contouring of the structural geology data.
2.0 LEARNING OUTCOMES
a) Students should able to use the geological compass.
b) Students should able to measures the dip and dip direction of any planes.
c) Students should able to plot poles of the structural geology data.
d) Students should able to plot contour from the structural geology data.
3.0 THEORY
Analysis of the orientation of structural geology data involves;
Plotting poles representing the dip and dip direction of each discontinuity. This plot will help to identify discontinuity sets, for which both the average orientation and the scatter (dispersion) can be calculated.
The second step in the analysis is to plot great circles representing the average orientation of each set, major discontinuities such as faults, and the dip and dip direction of the cut face.
4.0 EQUIMENT AND MATERIALS
Equal-area for plotting poles and great circles (Appendix C)
Equal-area polar net (Appendix D)
Kalsbeek counting net (Appendix E)
Tracing paper
Pencil
5.0 PROCEDURE
Poles can be plotted on the polar stereonet on which the dip direction is indicated on the periphery of the circle, and the dip is measured along radial lines with zero degrees at the center.
The procedure for plotting poles is to lay a sheet of tracing paper on the printed polar net and mark the north direction and each quadrant position around the edge of the outer circle. A mark is then made to show the pole that represents the orientation of each discontinuity as defined by its dip and dip direction. Poles for shallow dipping discontinuities lie close to the center of the circle, and poles of steeply dipping discontinuities lie close to the periphery of the circle.
Concentrations of pole orientations can be identified using Kalsbeek counting net. The Kalsbeek net is made up of mutually overlapping hexagons, each with an area of 1/100 of the full area of the stereonet.
Contouring is performed by overlaying the counting net on the pole and counting the number of poles in each hexagon; this number is marked on the net. These numbers of poles are converted into percentages by dividing each by the total number of poles and multiplying by 100. Once a percentage is written in each hexagon, contours can be developed by interpolation.
Prepared by : Lecturer Name : Aziman Bin Madun / Mohd Hazreek Bin Zainal Abidin Signature : Date : 8 January 2007
FACULTY : CIVIL & ENVIRONMENTAL ENGINEERING NO. OF PAGES: 2/5
DEPARTMENT : GEOTECHNICAL & TRANSPORTATION ENGINEERING
TOPIC : DETERMINE THE DISCONTINUITIES SETS AND MODES OF FAILURES OF STRUCTURAL GEOLOGY DATA DUE TO SLOPE (LAB 4b)
AMENDMENT DATE: 8/1/2007
3.2 THEORY
Mode of slope failures based on discontinuities sets plot.
Modes of failure Criteria
Circular i. Very weak material, highly jointed or fractured or weak soil ii. Homogenous soil
Planar
i. Dip direction lie within ± 200 from the “design slope” dip direction.
ii. ψf > ψp > j (slope angle>plane angle>friction angle) iii. Release surfaces must be present to define the lateral boundaries of the slide.
Wedge i. ψf > ψi > j (slope angle>intersection of 2 plane angle>friction angle) ii. driving force due to the weight of wedge must exceed the frictional resistance of the planes.
Toppling
i. The discontinuities dip direction must lie between ±10° of slope dip direction (opposite direction).
ii.
4.0 EQUIMENT AND MATERIALS
Equal-area equatorial net (Appendix C)
Tracing paper
Prepared by : Lecturer Name : Aziman Bin Madun / Mohd Hazreek Bin Zainal Abidin Signature : Date : 8 January 2007
pjf )90( 0
FACULTY : CIVIL & ENVIRONMENTAL ENGINEERING NO. OF PAGES: 3/3
DEPARTMENT : GEOTECHNICAL & TRANSPORTATION ENGINEERING
To identify which discontinuities are potential to fail and calculate the factor of safety.
2.0 LEARNING OUTCOMES
a) Students should able to calculate the safety factor for plane failure.
b) Students should able to calculate the safety factor for wedge failure.
3.0 THEORY
To obtain the factor of safety for planar is much simple rather than wedge. For plane, consideration on one discontinuity, besides wedge two discontinuities (sets). Two (2) conditions need to exam, wet and dry conditions.
4.0 EQUIMENT AND MATERIALS
Equal-area equatorial net (Appendix C)
Tracing paper
5.0 PROCEDURE
Determine the mode of failures
Used appropriate formula of planar or wedge given in APPENDIX A and B
The other information/properties from the site study and laboratory works are given as following:-
i. Rock unit weight, r = 25 kN/m3
ii. Rock friction angle,a =b = 30°
iii. Water unit weight, w = 9.81 kN/m3
iv. Cohesion of discontinuities, Ca = Cb = 50 kPa v. Height of slope = Height of wedge = Height of plane, H = 50 m vi. Tension crack depth, Z = Tension crack height, Zw = 1 meter vii. Upper slope data = 100° (dip direction) and 20° (dip angle) viii. Inclined angle of anchor (Ω) = (ψT) = 20° ix. Bars for Y25 = 10 ton = 100 kN
6.0 RESULT AND ANALYSIS
Factor of safety of plane failure in wet and dry condition
No of bars required to reinforced the plane failure
Factor of safety of wedge failure in wet and dry condition
7.0 QUESTION AND DISCUSSION
(1) For some cases, give the recommended value of safety factors for the rock slope in civil engineering / construction industry with some justifications. (2) Describe and explain the rock slope stabilization method. (3) Explain the main differences about the assessment of the Rock Slope and Soil Slope.
8.0 CONCLUSION
Prepared by : Lecturer Name : Aziman Bin Madun / Mohd Hazreek Bin Zainal Abidin Signature : Date : 8 January 2007
APPENDIX A SEMESTER/SESSION : COURSE : 3BFC
SUBJECT : GEOLOGI KEJURUTERAAN CODE : BFC 3013
Given:
FOS = cA + (W cosβ - U - V sinβ + T sin (Ω+β)) tan
W sinβ + V cosβ - T cos (Ω+β)
A = failure plane area = friction angle
c = cohesion U = vertical water pressure
W = weight of failure block V = horizontal water pressure
β = failure plane angle α = slope angle
H = height of plane Z = tensional cracks
T = tension of anchor Ω = inclined angle of anchor
γr = unit weight of rock γw = unit weight of water
A = (H-Z).cosec β
W = ½ r. H² [(1-(Z/H) ²)cot β – cot α]
U = ½ w.Zw .(H-Z).cosec β
V = ½ w.Zw
cosec = 1/sin sec=1/cos cot=1/tan
α β
W
H
Zw Z
U
V
Ω
T
APPENDIX B SEMESTER/SESSION : COURSE : 3BFC
SUBJECT : GEOLOGI KEJURUTERAAN CODE : BFC 3013
Given:
baba
t
TanYBTanXAYCXCFosww
H
).
2().
2()..(
3
aC = Cohesion b = Friction angle
Ht = height of wedge ψa = dip angle for plane a
ψb = dip angle for plane b ψ5= dip angle for wedge intersection
γ = unit weight of rock γw = unit weight of water
X, Y, A, B is factor which depend upon the geometry of wedge