JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III Year GEOTECHNICAL ENGINEERING Previous Question Paper (May/June - 2019 - R13)

Define density index and consistency index.

Write about consistency limits.

Write about principle of effective stress.

Write short notes on quick sand condition.

Write about mechanism of compaction.

Discuss any three factors affecting compaction.

Define immediate settlement and primary consolidation settlement.

Write about stress history of clay using e- logσ curves.

Define liquefaction and critical void ratio.

Write about laboratory vane shear test to measure undrained shear strength.

Derive the relation between void ratio and porosity.

A soil sample has a liquid limit of 75% and its plasticity index is 55 with a natural water content of 18%. Determine its plastic limit and liquidity index.

Explain step by step procedure to classify coarse grained soils.

A partially saturated sample has a moisture content of 15% and bulk unit weight of 21.5kN/m3. The specific gravity of solids is 2.67. Determine void ratio, degree of saturation.

Explain the laboratory procedure to determine coefficient of permeability by constant head method.

Determine the effective stress at a depth of 6 m below the ground level. The water table is at 2m below ground surface. The water content of the soil above water table is 10%. Take G = 2.65, e = 0.57. Neglect capillary flow.

Write about characteristics and uses of flownets.

In a laboratory permeability test, the discharge of water collected from a constant head permeameter in a period of 12 minutes is 250ml. The internal diameter of the permeameter is 8cm and the measured difference in head between two gauging points 15 cm vertically apart is 90cm. Calculate the coefficient of permeability.

Write briefly about field compaction equipment.

A circular area of radius 4m carries a uniformly distributed load of 150kN/m2. Determine the intensity of vertical pressure at 5m beneath the centre of the circle using Boussinesq’s theory.

Write briefly about compaction control.

Using Westergaurd’s theory, determine the vertical stress at a depth of 4m directly under the point load of 400kN acting at the surface of a soil mass and also at a horizontal distance of 3m.

Explain Taylor’s square root of time fitting method to determine coefficient of consolidation.

A 20mm thick consolidometer clay sample reached 80% consolidation in 1.2hours with double drainage. How long would it take for the clay layer from which this sample was obtained to reach 80% consolidation? The clay layer of 8m has single drainage.

Explain about preconsolidation pressure and its determination by Casagrande’s method.

A clay layer of 6m thick has a settlement of 25mm when the stress was increased from 50kN/m2 to 100kN/m2. What will be the settlement if the stress is increased from 100kN/m2 to 150kN/m2 for the same clay layer?

Explain about drainage conditions in Triaxial tests.

Discuss about shear strength of sands.

Write about shear strength of clays.

In an unconfined compression test, a sample of 7.5cm long and 3.5cm in diameter fails under a load of 90N at 10% strain. Compute the unconfined compressive strength and shear strength of the sample.