1. Choose the correct option.

Valid range for the degree of saturation of soil in percentage is

S 0

S 0

0 S 100

0 S 100

Uniformity coefficient of a soil is

always less than 1

always equal to 1

equal to or less than 1

equal to or greater than 1

Time factor for a clay layer is

a dimensional parameter

directly proportional to permeability of soil

inversely proportional to drainage path

independent of thickness of the clay layer

If a cohesive soil specimen is subjected to a vertical compressive load, the inclination of the cracks to the horizontal is

90°

45°

22.5°

0°

For a base failure, the depth factor Df is

zero

1

0 Df 1

Df 1

A soil having particles of nearly the same size is known as

well graded

uniformly graded

poorly graded

gap graded

The minimum centre to centre spacing of friction piles of diameter as per BIS code is

1·5 D

2 D

2·5 D

3 D

2. Explain the following terms for soils:

Coarse grained soil

Density Index

Liquidity Index

Well graded soil

The mass specific gravity of a soil equals 1·64. The specific gravity of solids is 2·70. Determine the void ratio under the assumption that the soil is perfectly dry.

3. Explain the Darcy's Law of flow of water through soil with suitable sketch.

Explain the Constant Head Permeability Test with suitable required sketch.

4. Discuss the advantages and disadvantages of direct shear test.

A vane, 10 em long and 8 cm in diameter, was pressed into soft clay at the bottom of a bore hole. Torque was applied and gradually increased to 45 N-m when failure took place. Calculate the cohesion of the clay in the natural state.

5. Explain the following field compaction methods in detail:

Rollers

Rammers

Vibrators

6. A square footing located at a depth of 1·3 m below the ground has to carry a safe load of 800kN. Find the size of the footing,if the desired factor of safety is 3. The soil has the following properties
Void ratio Degree of saturation
Specific gravity 2.67, c 8 30° Use Terzaghi's analysis.
For cj) Nc 37.2, Nq 22.5 and Ny 19·7.

7. Write short notes on any four of the following:

Split Spoon Sampler

Wash Boring

Geophysical Methods

Efficiency of Pile Group

Shallow Foundations and Well Foundations

Pressure distribution beneath a rigid footing