ANNA
UNIVERSITY :: CHENNAI – 600 025
B.E.
/ B.Tech. DEGREE EXAMINATIONS, APRIL / MAY 2004
Sixth
Semester
Civil
Engineering
CE340
– FOUNDATION ENGINEERING
(Model
Question Paper)
Time : Three hours Maximum : 100 Marks
Answer
ALL questions
Part
A (10 x 2 = 20 marks)
1. Give
the important parameter to fix the significant depth of exploration.
2. Mention
the factors that affect the sample disturbance.
3. What
are the different types of shear failures? Draw the sketches.
4. Mention
the components of settlement of foundation.
5. Differentiate
between cantilever footing and raft foundation.
6. List
out the methods for design of mat foundation.
7. Under
what circumstances the negative skin friction will develop.
8. List
out the necessities of pile foundation.
9. State
the assumptions made in Rankine’s earth pressure theory.
10. What
is the critical height of unsupported vertical cut in case of cohesive soils?
Part
B (5 x 16 = 80)
11. Design a
strap footing for the two columns. The allowable soil pressure is 100 kN/m2.
Load on left column = 600 kN. Load on right column = 1000 kN, size of left
column = 0.3m x 0.3m, size of right column = 0.4m x 0.4m, centre to centre
distance between columns = 6m. Eccentricity of footing of left column = 1m.
Take the allowable soil pressure as 100 kN/m2. Draw BMD and SFD.
Find the thickness of footings for the design B.M. (16)
12. (a) Explain the
factors governing the spacing, number and depth of bore holes for a
multi-storey building project. (4)
(b) Explain the SPT test with neat sketch and
give the correlation between SPT – N values and relative density. (8)
(c) What are the corrections required for SPT-N
value? (4)
(OR)
(a) What are the
commonly used methods of soil exploration? Explain any one method in detail. (8)
(b) What are the
basic requirements of good foundation? (4)
(c) What are the
necessary data required for plotting the bore log for any soil investigation
project. (4)
13. Calculate the
ultimate bearing capacity
per unit area of (i) Strip
footing 2.5m wide (ii) Square footing 4.75 x 4.75 m (iii) Circular footing
5.25m diameter. The footing is supported on a soil for which the following data
is available. g =
19.5 kN/m3 ; C=17.0
kN/m2,
j=200,
depth=1.75 m.
Use
Terzhaghi’s equation. Take Nc = 17.7, Nq = 7.5, and Nr
= 5.0. (16)
(OR)
A building
10m x 20m in plan is built on a raft foundation resting on the surface. The
soil profile consists of 4m dense sand over 3m thick silty clay layer resting
on rock. The water table is at 2m below ground level. Consolidation test
conducted on UDS of clay layer gave the results as follows.
Initial and
final void ratios and corresponding stresses are,
e0 = 1.1; s0’
= 2000 kN/m2; ef
= 1.0; sf’ =
1000 kN/m2; (16)
14. (a) Classify the pile based on functions, mode of
transfer of load and method of
installation with neat
sketches. (8)
(b)
Explain how do you determine pile load capacity from pile load test. (8)
(OR)
A
pile group consists of 9 piles of 30 cm diameter and 10 m length driven in
clay. Unconfined compressive strength
of soil is
200 kN/m2 and
insitu density of soil is 20 kN/m3. Determine the safe load
for the pile group. a =
0.6 and F.S. = 3. (16)
15. Determine the active pressure on the
retaining wall shown in figure by Culmann’s method. (16)
 |
(OR)
A retaining
wall 4m height with smooth backfill and horizontal surface subjected to a
surcharge of 36 kN/m2 uniformly. Saturated density of backfill is 18
kN/m3, f = 300,
C=0, find the active earth pressure and the point of application of the resultant
pressure. (16)
spl thanks to
Ms. AISHWARYA J
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