1 Application of Soil Mechanics Assignments Question No.1. (a) Briefly describe the Spencer’s (1967) method of slope stability analysis. Derive the expressions required for the same and critically discuss the stoical admissibility of the solution. (b) Draw a neat proportionate free hand sketch of a large earth and rockfill dam showing all the components and describe their functions. (Note: no credit will be given for disproportionate and badly drawn sketch) (c) With a neat sketch show how would you instrument a dam? Describe the function of each instrument. Question No. 2. An anchored retaining wall with water on both the sides of the wall and cohesive soil below the dredge line is shown in figure 1. Draw the pressure distribution diagram on the wall giving principal values. Find the embedment depth and anchor- rod force. Use F.S. =1.5 on cohesion. Use free earth support method. Assume k a = k a ’ =0.297 and k p = k p ’ =6.1. 2.4 m 6.7 m = 16.5 kN/m 3 , =30 0 sat = 20.2 kN/m 3 , =30 0 Sand Clay c = 72.0 kpa = 0 0 , sat = 19.2 kN/m 3 Dredge Line Water Table D Figure 1 F ar 1.2 m
1Application of Soil Mechanics Assignments Question No.1. (a)
Briefly describe the Spencers (1967) method of slope stability
analysis. Derive the expressions required for the same and
critically discuss the stoical admissibility of the solution. (b)
Draw a neat proportionate free hand sketch of a large earth and
rockfill dam showing
allthecomponentsanddescribetheirfunctions.(Note:nocreditwillbegivenfor
disproportionate and badly drawn sketch) (c) With a neat sketch
show how would you instrument a dam? Describe the function of each
instrument. Question No. 2. An anchored retaining wall with water
on both the sides of the wall and cohesive soil below the dredge
line is shown in figure 1. Draw the pressure distribution diagram
on the wall giving principal values. Find the embedment depth and
anchor- rod force. Use F.S. =1.5 on cohesion. Use free earth
support method. Assume ka =ka =0.297 and kp =kp =6.1. 2.4m6.7 m =
16.5 kN/m3, =300 sat= 20.2 kN/m3, =300Sand Clay c = 72.0 kpa = 00,
sat = 19.2 kN/m3 Dredge Line Water Table D Figure 1 Far1.2 m 2
Question No. 3. (a) A 10 m deep by 8 m wide open cut is to be made
in the sub-soil condition shown in figure 2.Check the bottom
stability and Design a suitable bracings system. Assume m =1.0 (b)
A rigid pipe with an outside diameter of 1m diameter is laid in a
ditch which is 1.5m wide at the top of the pipe. The pipe is
covered with 9.0 m of sandy soil backfill (k =0.18). Determine the
load on the pipe. Take =18 kN/m3. Brownish grey silty clay = 1.8
t/m3, cu = 4t/m2 Soft Marine clay = 1.7 t/m3, cu = 2t/m2 Stiff clay
= 1.9 t/m3, cu = 6t/m2 Sand N > 40 0- 3 -13 -16 Figure- 2 3
Question No. 4. (a)
BrieflydescribetheSeedandMartins(1966)approachforslopestability
analysis.(b) Consider a dam is located 80 km. away from the active
fault trace and the shock of magnitude 7.75 occurs. Considering
El-centro earthquake of 1940 (maximum horizontal
acceleration=0.33g) find the response of a dam having a time period
(T)of1sec.andadampingequalto5%.Howwouldyoudistributethe
acceleration along the height of the dam?
