GTE-2

1. Subject Code
CED1122 R12
VNR VIGNANA JYOTHI INSTITUTE OF ENGINEERING AND TECHNOLOGY
(AUTONOMOUS)
B.Tech. III Year II Semester Regular Examinations, May, 2015
GEOTECHNICAL ENGINEERING-II
(CE)
Time: 3Hours Max. Marks: 70M
PART-A
(Answer ALL Questions)
1. Answer in one sentence 5X1=5M
a) List the types of boring methods.
b) What is fellenous line?
c) List the types of retaining walls.
d) Define ultimate bearing capacity of soil.
e) What is test pile?
2. Answer the following in two sentence each 5X2= 10M
a) What is Borelogs?
b) What are different factors of safety used in finite slopes?
c) What is earth pressure at rest?
d) What is the effect of water table on bearing capacity of soil?
e) List the piles based on function.
3. Answer the following in brief 5X3=15M
a) What are different types of samples?
b) What is Taylor’s Stability Number?
c) Write the assumptions in Rankine’s earth pressure theory?
d) What are the factors affecting bearing capacity of soil?
e) What is the Negative skin friction?
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2. PART – B
Answer any FOUR Questions 4X10=40M
4. a) Explain the Electrical resistivity method used in soil exploration. 5M
b) The measured of N value in a borehole is found to be 20. The depth of the borehole was 15
m. The water table was located 1.5 m below ground level. The soil is fine silty and its unit
weight above and below water table were 16 and 21 KN/m3
respectively. Calculate the
corrected value of N. 5M
5. a) Derive an expression for the factor of safety of an infinite slope in cohesion less soil. What is
the effect of steady seepage parallel to the slope on the stability? 6M
b) Calculate the factor of safety with respect to cohesion of a clay slope laid at 1 in 2 to a height
of 10 m if γ=19 KN/m3
, C =25 KN/m2
and φ=12o
, what is the critical height of the slope in this
soil? Assume Taylor’s stability number as 0.064. 4M
6. a) Discuss Culmann ‘s method for the determination of active earth pressure. 5M
b) A 5m rigid retaining wall has to retain a backfill of dry, cohesionless soil having the
following properties: φ = 300
, void ratio , e = 0.74, G = 2.68. Plot the distribution of Rankine
lateral earth pressure on the wall and determine the magnitude and point of application of the
resultant thrust. 5M
7. a) A strip footing 1.2 m wide at its base is located at a depth of 1 m below the ground surface.
The properties of soil are γ=18 KN/m3
, C =30 KN/m2
and φ=20o
. Determine the safe bearing
capacity using a factor of safety of 3. Use Terzaghi’s analysis. Assume that the soil fails by local
shear. For φ = 20o
, Nc’
=11.8, Nq
’
=3.9, Nγ
’
=1.7 5M
b) Explain in detail about foundations on expansive soils. 5M
8. a) Explain the necessity of pile foundation 4M
b) A group of nine piles, 8 m long, is used as the foundation for a column. The piles are 30 cm
diameter with centre to centre spacing of 90 cm. The subsoil consists of clay with unconfined
compression strength of 180 KN/m2
. Estimate the safe load. (F.S =3.0) 6M
9. a) Discuss the limitations of the plate load test. 6M
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3. b) A rectangular footing (3 m x2 m) exerts a pressure of 100 KN/m2
on a cohesive soil having
Es = 5 x 104
KN/m2
and µ =0.50. Determine the immediate settlement at the centre, assuming it
to be (a) the footing is flexible , (b) the footing is rigid.
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