18BT173B/3

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KAKATIYA INSTITUTE OF TECHNOLOGY & SCIENCE, WARANGAL

(An Autonomous Institute under Kakatiya University, Warangal)
FACULTY OF ENGINEERING AND TECHNOLOGY
B. Tech. (CE) VII Semester (Regular & Supplementary) Examination, December 2022
U18CE703B: Foundation Engineering
Duration: 3 Hours] [Max. Marks: 60
Note: 1. Answer all the questions.
2. Assume if any data required and mention it explicitly
CDLL CO’s
1. a. Write the objectives of soil exploration? [1] R CO1
b. List methods of boring [1] R CO1
c. Summarize the assumptions made in the Terzaghi’s bearing capacity equation [1] U CO1
d. Draw load versus settlement curves for a pile load test [1] R CO2
e. Write Hiley’s dynamic formula for determination of pile capacity [1] R CO2
f. Explain the uses of well foundation? [1] U CO2
g. Write the tailor stability number formulae for factor of safety in slope stability [1] R CO3
analysis
h. When do you say the slope is infinite and give an example [1] U CO3
i. List types of clay minerals and which minerals causes high swelling of soil [1] U CO3
j. Draw a lateral pressure distribution diagram of an earthen embankment with [1] R CO4
6 m height and the water level on the upstream side is 5 m.
k. Define coefficient of earth pressure [1] U CO4
l. Summarize various types of machine foundations? [1] U CO4

2. a. (i). Write the difference between undisturbed and disturbed samples in soil [6] U CO1
investigation.
(ii). Describe split spoon cylinder sample. What is its use?
b. Compute the safe bearing capacity of a square footing of size 2.0 m located at a [6] U CO1
depth of 1.5 m in a cohesionless soil layer with an average sat = 20 kN/m3 and
’ = 350. The corresponding bearing capacity factors are given as follows: Nc =
57.8, Nq = 41.4 and Nγ = 42.4. assume FS as 2.5 and water table is quite deep.
What will be the percentage reduction in the value if the water table rises to
the surface due to unprecedented rainfall?
(OR)
2. c. With the help of a neat sketch, describe the procedure for conducting a plate [6] U CO1
load test and explain how the safe bearing capacity of the soil is determined
from the test data for both cohesive and cohesionless soil.
d. Determine the breadth of a strip footing required to carry a uniform load of [6] U CO1
600 kN/m with a factor of safety of 3 against shear failure. The footing is
situated at a depth of 1.0 m below the ground level. Determine the footing
size, if (i) the footing is loaded so fast that there is not enough time for the
excess porewater pressure to dissipate (ii) the footing is loaded gradually
giving enough time for the excess pore water pressure to dissipate.
Given: cu = 80 kPa; u = 0;  = 18.8 kN/m3; c’ = 0; ’ = 30o
For ’ = 30 ,
o Nc = 38; Nq = 23, Nr = 20

3. a. The following test data refers to pile load test carried out on a 400 mm [6] Ap CO2
diameter, 15 m long pile. Plot the load-settlement curve and estimate the
allowable load of the pile as per IS code.

Load on pile 150 200 250 300 400 500 600

(kN)
Settlement 1.45 2.25 2.75 3.6 5.75 10.5 30
of pile (mm)

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 18BT173B/3
b. (i) What are the different shapes of foundation wells and compare their merits [6] An CO2
and demerits.
(ii) Explain Negative skin-friction in case of pile foundations with a neat
sketch.
(OR)
3. c. (i). A group of 16 piles of 10 m length and 0.5 m diameter is installed in a 10 m [6] Ap CO2
thick stiff clay layer underlain by rock. The pile-soil adhesion factor is 0.4;
average shear strength of soil on the sides is 100 kPa; the undrained shear
strength of the soil at the base is also 100 kPa. Calculate the base resistance of a
single pile and assuming 100% efficiency, the group pile skin resistance is?
(ii). A 300mm diameter and 16 m long pile was driven by double-acting
hammer (total mass of 2800 kg and height of fall of 1.5 m). The driving was
done with a 2.5 cm cushion only. The average penetration in the last five
blows was 2.5 mm/blow. Calculate the safe load.
d. (i) What are the different shapes of well foundations and what are their [6] An CO2
comparative merits and demerits.
(ii) A well foundation to support the construction of a heavy bridge tilted on
the left in silty sand. List detailed procedure of various rectification techniques
to bring the well foundation into the required position.

4. a. (i). Explain various methods used for identification of expansive soil. [6] Ap CO3
(ii) Write a short note on problems associated with expansive soils. Give
general guidelines for design of under reamed pile based on IS code
b. A 5 m deep canal has side slopes of 1:1. The properties of soil are Cu = [6] E CO3
20kN/m2, φu = 100, e = 0.8 and G = 2.8. If the Taylor’s stability number is 0.108,
evaluate the factor of safety with respect to cohesion when the canal runs full.
Also find the same in case of sudden drawdown, its Taylor’s stability number
for this condition is 0.137.
(OR)
4. c. A cast in-situ two bulb under reamed pile having a diameter of 500 mm and 10 [6] Ap CO3
m length was placed in a soil stratum. The top 3.5 m soil is an expansive soil
had a Cu = 25. kPa. The below soil layer had a Cu = 40 kPa. Estimate the pile
load capacity in compression and tension. Take a = 0.5.
d. (i) Explain different types of slopes and their failures, in detail, with neat [6] E CO3
sketches.
(ii) Write a brief note on stability of earth dam slopes under different
conditions.

5. a. What are (i) Earth pressure at rest (ii) Active earth pressure and (iii) Passive [6] Ap CO4
earth pressure? Give one example each wherein a structure is designed for the
above earth pressure with neat sketches.
b. A retaining wall has a height of 6.5 m and the back fill soil properties are γ = [6] C CO4
18 kN/m3, Փ’= 29.50, C’ = 0 kPa. Determine (i) Rankine active force per unit
length of the wall and location of the resultant (ii). Rankine passive force per
unit length of the wall and location of the resultant.
(OR)
5. c. A retaining wall, 6 m high, retains dry sand with an angle of friction of 30° and [6] Ap CO4
unit weight of 18.9 kN/m3. Compute the earth pressures at rest and active
respectively. If the water table rises to the top of the wall, determine the
increase in the thrust on the wall. Assume the submerged unit weight of sand
as 10 kN/m3.
d. The government of Telangana proposed a special industrial zone to become a [6] C CO4
manufacturing hub. To accommodate all types of heavy machinery, what type
of machine foundations would you propose, explain them briefly with neat
sketches.

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