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Seat No.: Enrolment
GUJARAT TECHNOLOGICAL UNIVERSITY
ME SEMESTER I EXAMINATION SUMMER 2017
Subject Code: 2712009 Date:11/05/2017
Subject Name: Advanced Foundation Engineering
Time: 02:30 pm to 05:00 pm Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. Use of IS: 8009(part I IS:2911-2010, IS:5249-1992, IS:1904, IS:6403, IS:2950(part and other related IS code are permitted.
Q.1

Explain in detail any one method of determining the damping of soil-foundation system.
07

Explain the vertical and horizontal load resisting mechanism in shallow and deep foundation (pile foundation) along with suitable sketches.
07
Q.2

A cyclic plate load test was carried out at a depth of 3 using a 30 cm x 30 cm test plate on a deposit of silty sand to estimate the elastic co-efficient for the design of machine foundation. The elastic settlement obtain in each cycle calculated from test result in each cycle are as follow:
Load intensity
25
50
75
100
150
200
250
Elastic settlement
0.10
0.15
0.35
0.60
1
1
1.80
Determine the value of Cu, CØ, for 10 m2 base area.
07

A reciprocating machine is symmetrically mounted on a block of size 4 m x 3m x 3.5 m high as shown in figure below. The soil at the site is sandy in nature having Ø 350 and γsat 20 kN/m3. The water table lies at a depth of 3 m below the ground surface. The block is embedded in the ground by 2 m depth. The machine vibrating vertically at a speed of 250 rpm generates maximum unbalance vertical force 2.5 kN.
The machine weight is small in comparison to the weight of the foundation. The limiting amplitude of the machine is 150 microns. A block resonance test was conducted at the site to evaluate the dynamic elastic constants. The data obtain from the test are:
Cu 3.62 x 104 kN/m3.
G 1.10 x 104 kN/m2.
E 2.98 x 104 kN/m2.
0.35.
Determine the natural frequency and amplitudes by weightless spring-mass model.
07
2
OR

Determine the natural frequency and amplitudes in above examples by Elastic half space approach.
07
Q.3

The following data was obtained in a vertical pile load test on a 400 mm diameter of pile:
Load
5
10
20
30
40
50
60
settlement
2.5
4
9.5
16.5
27
40.5
61
Plot the load settlement curve and determine the allowable load as per IS code.
07

A precast circular concrete pile of 400 mm diameter in a prebored hole is of 16 m length installed in a deposit of sand. If the co-efficient of subgrade reaction 10 x 106 N/m3. Find the deflection of the pile head as per IS:2911:2010 considering it as free head pile under a horizontal force of 30 kN. Assume Epile 20 kN/mm2.
07
OR
Q.3

Design a friction pile group to carry a load of 2500 kN including the weight of the pile cap at a site where the soil is uniform clay to a depth of 18 m underlain by rock. The average unconfined compressive strength of the clay is 70 kN/m2. A factor of safety 2.5 is required against shear failure. Assume adhesion factor α 1. The pile is of 10 m length with 0.5 m diameter.
07

In the above example a assuming the clay to be of normal sensitivity and normally loaded with liquid limit of 60 compute the settlement of pile group as per guidelines given in IS: 8009(part-II). The unit weight of clay γ 16 kN/m3.
07
Q.4

Carry out the size proportioning of a TRAPEZOIDAL combined footing for a given data:
1. LHS column (W1 1800 kN) and RHS column (W2 1200 kN)
2. Centre to centre distance between column axis 6.5 m.
3. Property lines: 1 m on left side from axis of LHS column.
4. SBC 170 kPa.
Also draw only S.F. diagram mentioning typical values.
07

A rectangular shallow footing has a size of 2 m x 3m has to be transmit a load of a column at a depth of 1.6m. Calculate the safe bearing capacity of a footing as per IS: 6403 with factor of safety 3 against shear failure. The soil has following properties: C 10 kN/m2, Ø 32.50, γ 18 kN/m3. The depth of footing is 1.6 m from ground level.
07
OR
Q.4

A footing 4m x 2.5m in plan, transmits a pressure of 200 kN/m2 on a cohesive soil having Es 6 x 104 kN/m2 and 0.5. Determine the immediate settlement of the footing at the centre as per IS:8009(part- assuming it to be
a flexible footing and
a rigid footing.
07
3

Answer the following w.r.t. Raft foundation:
What is minimum depth of foundation.
Under which situations one can go for raft foundation.
State the criteria for considering raft as rigid or flexible for analysis.
Draw a typical sketch for various types of raft foundation.
07
Q.5

State the difference between Elastic half space approach and Winkler spring-mass model approach for carrying out Soil-Structure Interaction analysis.
07

Suggest different measures to be taken for foundation on expansive soil along with suitable justification.
07
OR
Q.5

Enlist the conditions responsible for Liquefaction to take place in soil. Also suggest the different way to mitigate the Liquefaction with suitable justification.
07

Explain the stability analysis of a Well foundation.
07