Name : ARJIT CHAUHAN
PS NO : 40046794
1. Given Data
DEPTH (Z) = 2.5m
COHESION (C)= 0.7Kg/cm2 = (0.7*98.068) = 68.64KPa
DENSITY = 1.85 g/cm3 = (1.85*9.81) = 18.14 kN/m3
Total Load (P) = 520 Tonne = (520*9.81) = 510.12 kN
LOAD FACTOR = 2.5
Nc = 10 , Nq=4 , Nf = 2
Using Terzaghi’s formula and Pressure formula
B= 3.44m
So, Size of Footing = 3.44m x 3.44m
2. Subgrade modulus reaction is measure of stiffness of soil. Can be calculated by dividing load
intensity by settlement. Its unit is kN/m3 or kg/cm3
3. c. (1-sinφ/1+sinφ)
4. Earth Pressure at rest = 1-sinφ , when there is no movement of wall , while the earth pressure
at active condition is (1-sinφ/1+sinφ) , when wall moves away from the soil, the soil expands and
horizontal stress decreases.
At Rest condition the earth pressure will be maximum as resistive force is acting against the
earth pressure is greater than active case.
As per formula at rest = 1-sinφ.
As per formula (1-sinφ/1+sinφ).
5. h.All of the above.
6. qult = 300kPA , z= 1m, density = 20kN/m3 , F.O.S = 2.5
Qnet = 300-20 = 280 .
SBC = (280/2.5) = 112kPa
7. p . Shear failure and Settlement
8. t. Will be more than 100% for pile groups in cohesion less soil and less than 100% for
those in cohesive soil.
9. The allowable settlement for Pile for axial compression is 12mm for pile diameter less than
600mm.
And allowable settlement for Pile for axial compression is 18mm for pile diameter greater than
600mm.
10. SPT number or N-value are the measure of blows into the soil by 30cm, after initial seating
of 15cm, using 63.5kg hammer falling from 75cm as per IS 2131.
11. Plate load test is conducted to determine the settlement of soil , ultimate bearing capacity and
modulus of sub grade reaction.
12. Fly ash stabilization, Geosynthetics, jet grouting and injection, Blasting.
13.Elastic settlements occur immediately after loading, it happens due to compression of coarsegrained soil like sand and small gravels, it is based on elastic theory.
Consolidation settlement occurs over the period of time, it happens due to expulsion of water
from pores, in fine grained soils like clay and silts, it is based on Terzaghi’s consolidation theory.
14. Types of pile test :
A. Vertical Load test :
1. Static Load Test – Dead weights are applied on Test pile in vertical directions until the
maximum load reach or pile shows settlement or failure. Dial gauges are placed to record the
load acting on the Test Pile. Load vs Settlement curve is plotted. IS 2911 (Part 4) is used.
2.Dynamic Load Test – A Hammer strikes at the top of the test pile and sensors are placed
around the base of pile to record the wave and signals to data acquisition system to determine the
pile capacity and stress distribution.
B. Lateral Load Test – Dead load with hydraulic jack and plate placed laterally to apply
lateral load, dial gauges are placed at pile head to measure displacement at every stage.
Maximum deflection shall not exceed 5mm. IS 2911 (Part 4) is used.
C. Pull Out test – Test is conducted to determine the uplift or tensile capacity of pile.
Hydraulic jack applies the upward pressure on the pile; reaction is taken from anchor piles or
concrete deadweight platform. Dial gauges placed at pile head measure the vertical uplift. IS
2911 (Part 4) is used.
D. Pile Integrity Test – This test detects cracks, voids, necking, honeycombing, pile
continuity issues. In this test a small hammer is used to strike on the top the pile head, a
geophone is placed on the top of the pile to record the response (stress wave), these waves
recorded in the software that detects the defects like changes in cross section, voids. These tests
are quick and easy to perform.IS 2911 (Part 4) is used.
15. Seismic downhole test – Shear Modulus, Poisson's ratio, Elastic Modulus.