Hall Ticket No Question Paper Code: ACE006
INSTITUTE OF AERONAUTICAL ENGINEERING
(Autonomous)
B.Tech IV Semester End Examinations (Regular) May, 2018
Regulation: IARE R16
GEOTECHNICAL ENGINEERING
Time: 3 Hours Max Marks: 70
Answer ONE Question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
UNIT I
1. What are the corrections to be applied in hydrometer analysis? Explain the principle of hydrometer
analysis.
A soil specimen has water content of 10% and a wet unit weight of 20kN/m3. If the specific
gravity of solids is 2.70, determine the dry unit weight, void ratio and degree of saturation. Take

w =19kN/m3.
2. What are the different types of soil structures? Explain them with neat sketch.
A soil has a liquid limit of 25% and flow index of 12.5%, if the plastic limit is determine
the plasticity index and toughness index.
If the water content of the soil in its natural condition in the field is 20%. Find the liquidity
index.
UNIT II
3. Define permeability. Explain the factors affecting permeability of soil.
Compute the coefficient of permeability of a soil on which a falling head test has been carried
out. Area of sample =80 cm2, area of stand pipe 4cm2 and length of soil sample 15cm.
Time Vs Head difference readings are as given in Table 1.
Table 1
Time (minute) 0 27 60
Head difference, h 107 105 103
4. Explain about total stress, neutral stress and effective stress conditions. Determine the factor of
safety with respect to cohesion for a submerged embankment 25m high and having a slope of 400
is subjected to sudden drawdown.
sat =18kN/m3).
A saturated sand layer over a clay stratum is 5m in depth. The water table is 1.5m below ground
level. If the bulk density of saturated sand is 17.66kN/m3, calculate the effective and neutral
pressure on top of the clay layer.
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UNIT III
5. Explain the laboratory test procedure of Modified Proctor Test of compaction.
A concentrated load of 2000kN is applied at the ground surface. Determine the vertical stress
at a point P which is 6m directly below the load. Also calculate the vertical stress at a point R
which is at a depth of 6m but at a horizontal distance of 5m from the axis of the load.
6. Define compaction. Explain the various factors affecting the compaction.
Summarize the assumptions and limitations of Boussinesq's solution.
UNIT IV
7. Explain the square root of time method and logarithm of time method for the determination of
coefficient of consolidation.
A clay stratum 5m thick has the initial void ratio of 1.50 and the effective overburden pressure of
120kN/m2. When the sample is subjected to an increase of pressure of 120kN/m2, the void ratio
reduces to 1.44. Determine the coefficient of the volume compressibility and the final settlement
of the stratum.
8. Explain about Initial consolidation, Primary and Secondary consolidation.
Define coefficient of compressibility, compression index and expansion index. Derive an expression
for void ratio using height of solids method.
UNIT V
9. Write the test procedure of Triaxial Test and explain the merits and demerits of Triaxial Test.

A sample of dry cohesionless soil was tested in a triaxial machine. If the angle of shearing
resistance was 360 and confining pressure 100kN/m2, determine the deviator stress at which the
sample failed.
10. Explain the Mohr-Coulomb theory. And also draw the failure envelopes.
An undrained triaxial compression test was conducted on a sample of compacted clay. Pore-water
pressure was measured after the application of the cell pressure and also at failure, as given below.
Find the pore pressure coefficients A and B.
i. Consolidation stage:
Change in cell pressure 0 to 100kN/m2
Change in pore water pressure -60 to +10kN/m2
ii. Shearing stage:
Deviator stress at failure 500kN/m2
Pore pressure at failure -70kN/m2