Test Papers / Previous Question Papers of IGNOU ET501 (B) Foundation Engineering December 2005

B.Tech. Civil (Construction Management)
Term-End Examination

December, 2005

ET-501(B): FOUNDATION ENGINEERING

Time: 3 hours
Maximum Marks: 70

1. Answer any four of the following: (4x10=40)

(a) Discuss the different methods of site exploration by boring.

(b) Briefly desctibe the following :

(i) Depth of exploration
(ii) Recovery ratios
(iii) Modes of failures in shallow foundation
(v) Ultimate bearing capacity

(c) Determine the net ultimate bearing capacity for a square foundation shown in the figure below. The water table is located well below the base. Use Terzaghi's bearing capacity factors.

DIAGRAM

Soil properties
γ = 18 kN/m³
c' = 16 kN/m2
π' = 30⁰
Dr = 90⁰ (dense)
(N_c = 37.2, N_q = 22.5, N_γ = 19.7)

(d) The foundation for a circular tank is to be of diameler 18 m and founded at a depth of 2.5 m.

The soil properties are :

c' = 0, π' = 34⁰, γ= 19 kN/m³.

Determine the ultimate bearing capacity when the ground water is

(i) 2-0 m below foundation
(ii) at the base of the foundation, and
(iii) at 1.0 m below ground surface.

Use correction factors to consider the effect of water table. Use Terzaghi's equation. ( N_q = 36.5 , N_γ = 35.0 )

(e) Two columns are loaded as shown in the figure below. Determine the dimensions of the rectangular combined footing to carry the column loads.

DIAGRAM

Size of column A is 45 x 45 cm and of column B is 50 x 50 cm, Allowable soil pressure is 300 kPa.

(f) Discuss the factors affecting the bearing capacity of soil.

2. Answer any three of the following: (3x10=30)

(a) Explain the methods of controlling settlement.

(b) A retaining wall 8 m high with a smooth veriical back retains a two layer dry cohesionless backfill with the following properties :

Determine the total lateral earth force acting on the wall and its line of action.

(c) A load of 2000 kN is being taken by a square column footing. Side of the column is 3 m, footing rests on a silty soil with a Poisson's ratio = 0 3. Modulus of elasticity of the soil is 50 MPa. Find the settlement at the centre and at the edge of the fooilng. Assume influence factor for centre = 1.12 and at edge = 0.56.

Briefly describe the types of piles based on the type of materials used to construct them.

Enumerate the methods for determining the dynamic properties of soil. Describe the Seismic cone Penetration Test.