JNTU B.Tech III SOIL MECHANICS Previous Question Paper (August/September - 2024 - R16)

Explain classification of soil as per Indian standard.

A moist soil sample has volume 464 cc in natural state and weight of 793 gm. Dry weight is 735 gm. The specific gravity of soil grain is 2.68. Determine (i) Void ratio, (ii) Porosity, (iii) Water content, and (iv) Degree of saturation.

Describe phase diagrams of soil separately with sketches for each phase, level all components of soil and give symbols of its various index properties.

From a particle size distribution curve following readings were taken: Liquid limit 25%, plastic limit 15%, effective size of particle 0.17 mm, 30% finer size 0.38 mm, and 60% finer size 0.78 mm. Calculate uniformity coefficient, coefficient of curvature, type of soil and its Plasticity Index.

Explain the step by step procedure for estimation of permeability of soil by constant head method and derive the equation.

Find the permeability of soil through which 450ml of water pass 6cm in 15 minutes across a cross section area of 60cm2 under the constant head flow of 50cm.

Explain characteristics and application of flow net.

Explain the following: i) Effective stress ii) Quick sand condition iii) Seepage through soils.

Explain assumptions of Boussinesq’s theory in detail and how is it different from Westergaard’s theory.

A circular area is loaded with the uniform load intensity of 10 t/m2 at ground surface. Calculate the vertical pressure at a point P situated on the vertical line through the centre of loaded area. Such that the area subtends an angle 90 deg at P. Use Boussinesq’s analysis.

Write a detailed note field compaction equipment.

During proctor test of compaction, the following readings were recorded in the laboratory. Draw compaction curve and find O.M.C and M.D.D.

Explain the terms consolidation and pre-consolidation pressure. Explain the procedure for determination of pre-consolidation pressure.

A layer of soft clay is 6m thick and lies under a newly constructed building. The weight of sand overlying the clay layer produces a pressure of 2.6 kg/cm2 and the new construction increases the pressure by 1.0 kg/cm2. If the compression index is 0.5. Compute the settlement. Water content is 40% and specific gravity of grains is 2.65.

Discuss the salient features of Terzhagi’s consolidation theory. Explain why it is used despite of the limitations.

How many days would be required by a clay stratum 5 m thick, draining at both ends with an average value of coefficient of consolidation = 50 × 10-4 cm2/sec, to attain 50 % of its ultimate settlement.

Describe in detail how you will obtain failure envelope by drawing Mohr circle method from data from a direct box shear test.

Using the observations of Box Shear Test on Soil sample at its failure, Calculate Cohesion value of given soil sample. Normal stress: 25 N/mm2, Shear Stress: 15 N/mm2, Angle of friction: 250.

Classify shear tests based on drainage condition. How can we achieve these drainage condition in direct box shear test and triaxial tests? Where do you recommend the use of these tests in practise?

List different types of laboratory tests for strength parameters. Explain any one of the test.