Distinguish between the following:

Liquid Limit and Liquidity Index,

Density and Relative Density.

A soil has a plastic limit of 25% and a plasticity index of 30. If the natural water content of the soil is determine the liquidity index and consistency index.

The discharge of water collected from a constant head permeameter in a period of 15 minutes is 500 ml. The internal diameter of the permeameter is 5 cm and the measured difference in head between two gauging points 15 cm vertically apart is 40 cm. Calculate the coefficient of permeability.

Write the factors that affect the permeability of a soil stratum. If K1, K2, K3 are the permeabilities of layers h1, h2, h3 thick, what is its equivalent permeability in the horizontal and vertical direction

Explain the stress distribution in soils for concentrated loads by Boussinesq's equation.

What do you understand by "Pressure bulb"? Illustrate with sketches.

Explain the Mohr-Coulomb strength envelope. Sketch .the stress-strain relationship for dense and loose sand.

The stresses at failure of the failure plane in a cohesionless soil mass are
Shear stress
Normal stress =10 kN/m^2.
Determine the resultant stress on the failure plane, the angle of internal friction of the soil and the angle of inclination of the failure plane to the major principal plane.

5. What are the advantages and disadvantages of a triaxial compression test? Briefly explain how do you conduct the test and compute the shear parameters for the soil from the test data.

Describe a suitable method of stability analysis of slopes in

purely saturated cohesive soil,

cohesionless soil.

Critically discuss the basic assumptions made in the stability analysis of slopes.

7. Write short notes on the following:

Texture and Structure of Soils

Soil Formation

The following classification tests were performed on a specimen recorded from a borehole from a depth of 20 feet. The test sample is black with a strong odour. Give the group symbol and group nature.

Sieve Analysis, Finer Atterberg Limit
No.1 No.4 No. 200 Liquid Limit Plastic Limit
100 96 90 80 55

Define the following:

Uniformity Coefficient

Curvature Coefficient

Relative Density [Density Index]

Sensitivity

Activity

A drainage pipe is clogged with sand whose hydraulic conductivity is found to be 9·0 cm/s. The average difference in headwater and tailwater elevation is 1·2 m and it has been observed that there is a flow of 330 cm^3/s through the pipe. If the pipe is 6 m long and has a cross-section area of 20 cm^2 what length of the pipe is filled with sand?

A horizontal stratified soil deposit consists of three layers each uniform in it self. The permeabilities of the three layers are 8 x 52 x and 6 x cm/s and their thicknesses are 3 and 10 m respectively. Find the effective average permeability of the deposit in the horizontal and vertical direction.

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10.(a) Define the terms "Compression index", "Coefficient of Consolidation" and "Coefficient of Compressibility" and indicate their units and symbols.

A soil in the borrow pit is at a dry density of 17 kN/m^3 with a moisture content of 10%. The soil is excavated from this pit and compacted in an embankment to dry density of 18 kN/m^3 with a moisture· content of 15%. Compute the quantity of soil to be excavated from the borrow pit and the amount of water to be added for 10 m^3 of compacted soil in the embankment.