Ranchi University 2010-2nd Sem B.Tech Civil Engineering IV Supplementary s, ADVANCED FOUNDATION ENGINEERING - Question Paper

IV B.Tech II Semester Supplementary Examinations, April 2010
ADVANCED FOUNDATION ENGINEERING
(Civil Engineering)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
? ? ? ? ?
1. (a) explain critically and in a comparative manner, the bearing capacity theories
of Terzaghi and Meyerhof with special reference to
i. the suitability of the theories to various foundation conditions
ii. the rupture surfaces and the failure planes
iii. the assumptions made
iv. the bearing capacity equations and the charts given and
v. the procedure to obtain the bearing capacity of soils.
(b) What is the ultimate load carrying capacity of a square footing of size 2.0m×2.0m
with an eccentricity of 0.4 m? The depth of the footing is 0.6m. The soil prop-
erties are: °= 20 kN/m3, c= 12 kN/m2 and ;= 300. For ;= 300, Nc= 30, Nq=
18 and N°= 15. [10+6]
2. (a) discuss the recommended construction practices to avoid detrimental differ-
ential settlement in large structures.
(b) A clay layer 25m thick has a saturated unit weight of 19.2 kN/m3. Ground
water level occurs at a depth of 5m. It is proposed to construct a reinforced
concrete foundation, 12.5m × 50m, on top of the layer, to transmit a uniform
pressure of 150 kN/m2. Determine the settlement at its centre, assuming that
the void ratio drops from 0.725 to 0.700 due to loading. E for the clay is 30
MN/m2. [8+8]
3. Design of friction pile group to carry a load of 3000 kN including the weight of the
pile cap at a site where the soil is uniform clay to a depth of 20m, underlain by
rock. avg. unconfined compressive strength of the clay is 70 kN/m2 and unit
weight of clay is 17 kN/m3. The clay may be presumed to be of normal sensitivity
and normal loaded with liquid limit of 60%. A factor of safety of three is needed
against shear failure. Also calculate the settlement of the group assuming the load
to be transferred at 2/3 length of the pile. [16]
4. (a) What is down drag force on a pile? How to determine the down drag force in
single piles and also in a group of piles?
(b) A square pile group of 16 piles pass through a filled up soil of three m depth. The
pile diameter is 250 mm and pile spacing is 750 mm. If unit cohesion of the
material is 18 kN/m2 and unit weight is 15 kN/m3, calculate the negative skin
friction on the group. [10+6]
5. (a) What considerations govern the fixing of the depth of a well foundation?
1 of 2
www.jntuworld.com
Code No: G0101/RR RR
(b) How is the allowable bearing pressure of a well foundation in sand determined?
(c) explain the different remedial measures that can be adopted to rectify the tilts
in well foundations. [4+4+8]
6. (a) explain the stability calculations for bulkheads.
(b) For the anchored sheet pile shown in Figure 1, determine the theroretical and
true depth of penetration, the anchor force for unit length of the wall and
maximum moment. presume free-earth support, [8+8]
Figure 1:
7. (a) elaborate the factors influencing the swell pressure of soil?
(b) elaborate the tests available to determine the swell pressure of an expansive
soil and discuss any 1 of them very clearly? [8+8]
8. (a) discuss the principle and execution of lime column technique.
(b) What is CNS layer? How to use it? elaborate its limitations? [8+8]
? ?

Earning:   Approval pending.