JNTU B.Tech III GEOTECHNICAL ENGINEERING Previous Question Paper (May - 2018 - R13)

A fully saturated soil sample has a water content of 35% and specific gravity of 2.65. Determine its porosity, saturated unit weight and dry unit weight.

A clay soil has a liquid limit of 62% and plastic limit of 34%. Classify the soil as per the IS classification.

The effective size of a silt is 0.01 mm. The void ratio is 0.7. What is the height of capillary rise of water in this soil?

Define the terms discharge velocity and seepage velocity.

State the Boussinesq’s and Westergaard’s theories for point load.

Explain briefly the mechanism of compaction.

How do you determine the pre-consolidated pressure?

Write a short note on stress history of clay.

Define the term dilatancy.

Explain Liquefaction.

A clay soil has a liquid limit of 52%. The volume of the soil sample in the shrinkage dish at the liquid limit is 0.0401 × 10^-3 m³ and its shrinks to a volume of 0.0261 × 10^-3 m³ at the shrinkage limit. The specific gravity of solids is 2.72. Determine the shrinkage limit of the soil.

Write a brief note on soil formation.

Distinguish between the residual soil and transported soil.

What are building blocks of clay minerals? Explain three common groups of clay minerals.

Discuss the different methods to determine the permeability of a soil sample?

A saturated sand layer over a clay stratum is 5m in depth. The water is 1.5 m below ground level. If the bulk density of saturated sand is 1.8 g cc^-1, calculate the effective and neutral pressure on the top of the clay layer.

Discuss briefly the merits and demerits of different methods determining permeability and special applications.

Write a short on characteristics of flow net. Give its uses.

A concentrated point load of 200 kN acts at the ground surface. Find the intensity of vertical pressure at a depth of 10 meters below the ground surface, and situated on the axis of loading. What will be the vertical pressure at a point at a depth at 5 m and at a distance of 2 m from the axis of loading? Use Westergaard analysis taking μ = 0.

Discuss the factors which affect compaction of soils in embankments.

How do you estimate the field e-p curve of an over consolidated clay?

Briefly explain the physical meaning of the coefficient of consolidation.

Why does it take infinite time for complete consolidation to occur?

Explain the Terzaghi’s 1-D consolidation theory.

Define critical void ratio. Explain the shear behavior of a soil whose void ratio is less than the critical ratio.

A vane of 80 mm diameter and 160 mm height has been pushed into an in-situ soft clay at the bottom of a bore hole. The torque required to rotate the vane was 76 N-m. Determine the undrained shear strength of the clay. After the test, the vane was rotated several times and the ultimate torque was found to be 50 N-m. Estimate the sensitivity of the clay.

Discuss the type of laboratory triaxial test you would recommend for the initial stability of a foundation on saturated clay.

Explain why the angle of failure plane observed in a shear test might differ more often from that predicted from Mohr diagram at failure.