STUPIDSID
1 (a)
Differentiate between Finite and Infinite slope. Explain the method of checking the stability of a finite slope by Swedish method of Slices for a Cohesive frictional soil.
7 M
1 (b)
An embankment is inclined at an angle of 40° and its height is 10m. The angle of shearing resistance is 20° and cohesion intercept is 100 kPa. The unit weight of soil is 19 kN/m3. If the Taylor stability number is 0.06, find the factor of safety with respect to cohesion.
7 M
2 (a)
Write short notes on
I. Active and passive earth pressure,
II. Rankine's earth pressure theory,
III. Mohr circle diagram for active and passive state.
I. Active and passive earth pressure,
II. Rankine's earth pressure theory,
III. Mohr circle diagram for active and passive state.
7 M
2 (b)
A Retaining wall with a smooth vertical back retains a purely cohesive
fill. Height of wall is 11m. Unit weight of fill is 20 kN/m3. Cohesion is
10kPa and Φu=0.0°. What is the total active Rankine thrust on the
wall? At what depth is the intensity of pressure zero and where does
the resultant thrust act?
7 M
2 (c)
A retaining wall 5.0 m high with a smooth vertical back retains a dry
sandy backfill of unit weight 18 kN/m 3 and Φ=30°. The backfill
carries a uniformly distributed load of 10 kPa. Find by Rankine's
theory the total active pressure per m length of the wall and its point of
application above the base. If the water table rises behind the back of
the wall to an elevation of 2.0 m below the top of the wall, what is the
change in the total active pressure per m of the wall? Assume no
change in Φ.
7 M
3 (a)
What are the basic assumptions in Boussiness's theory of stress
distribution in soils? Show the vertical stress distribution on a
horizontal plane at a given depth. Explain pressure bulb.
7 M
3 (b)
A concentrated load of 50kN acts on the surface of a homogeneous soil
mass of large extent. Find the stress intensity at a depth of 5m and
a) Directly under the load, and
b) At a horizontal dist of 5m. Use Boussiness's equation.
a) Directly under the load, and
b) At a horizontal dist of 5m. Use Boussiness's equation.
7 M
3 (c)
Describe the standard penetration test used in soil exploration. List the
information that can be obtained by the test when made in (i) clay, (ii)
sand.
Comment on the correction factor for N- values for the dry sand and
submerged fine sand.
7 M
3 (d)
Compute the area ratio of a thin walled tube sampler having an external diameter of 100 mm and a wall thickness of 2.0 mm. Do you recommend the sampler for obtaining undisturbed soil
samples? Why?
7 M
4 (a)
Discuss the various factors that affect the bearing capacity of a shallow
footing. How do you ascertain whether a footing will fail in local or
general shear failure?
7 M
4 (b)
Compute the safe bearing capacity of a square footing 2.0 m*2.0 m,
located at a depth of 1.5 m below the ground level in a soil of unit
weight 19 kN/m3,= Φ =20°, Nc=17.7, Nq=7.4, Nγ=5.0. Assume a
suitable factor of safety. The water table is very deep. If the water table
touches the base of the footing, find the reduction in safe bearing
Capacity.
7 M
4 (c)
Explain general and local shear failure. Bring out clearly the effect of
water table on the bearing capacity of a footing.
7 M
4 (d)
A strip footing 1.4 m wide, rests on the surface of a dry cohesionless
soil having Φ=20° and γ=18 kN/m3. If the water table rises
temporarily to the surface due to flooding, calculate the percentage
reduction in the ultimate capacity of the soil. Assume Nγ=5.0.
7 M
5 (a)
What do you mean by pile group efficiency? What are the various
formulae to find it?
7 M
5 (b)
A Square pile (3*3=9 piles) are embedded in clayey bed (Cu = 100
kPa). The c/c spacing is kept as 3d. The length and diameter of the pile
are 10m and 0.3m respectively. If α = 0.6, calculate the pile group
capacity considering it as friction pile group.
7 M
5 (c)
What is the basis on which the dynamic formulae are derived? Mention two well known dynamic formulae and explain the symbols involved.
7 M
5 (d)
A 30 cm diameter pile, 15 m long, is driven in a deposit of medium
dense sand (Φ=36°, Nγ=40, Nq=42). The unit weight of sand is 15 kN/m3 . What is allowable load with factor of safety 3? Assume lateral
earth pressure coefficient = 0.6.
7 M
More question papers from Geotechnical Engineering - 2