JNTU B.Tech III GEOTECHNICAL ENGINEERING Previous Question Paper (August - 2022 - R18)

Develop relationship between degree of saturation, void ratio, water content and Specific gravity.

Calculate the void ratio, porosity and degree of saturation of a soil sample if it has a wet density of 2.0g/cc and dry density of 1.8g/cc. Take specific gravity of solids as 2.7.

Explain I.S classification of soils.

Estimate the shrinkage limit of a clayey soil whose void ratio in the dry state is 0.55 and the specific gravity of solids is 2.75.

Identify the factors that influence the permeability of soil.

A 100mm long specimen is subjected to a variable head permeability test in which the initial head of 360mm drops to 120mm in 15minutes. Determine the permeability, if the diameter of the stand pipe is 1/10th of the specimen.

Elaborate the concept of total, neutral and effective stresses with diagrams.

A 3m thick sandy stratum has a coefficient of permeability of 3×10^-2 m/s. a separate test gave a porosity of 40% and bulk unit weight of 20.6 kN/m³ at a moisture content of 31%. Determine the head at which upward seepage will cause a quick sand condition. Also find the discharge velocity and seepage velocity under quick sand condition.

For a sedimentary soil deposit, which solution is more appropriate—Boussinesq’s or Westergaard’s? Why? State the assumptions involved in Westergaard’s theory.

A circular ring type foundation for a water tank exerts on the soil a uniformly distributed pressure of 20kN/m². The outer diameter of the ring foundation is 10m and inner diameter is 8m. Estimate the vertical stress along a vertical line through the center of the foundation at 2m below the foundation.

Identify the factors that influence compaction.

Following data was obtained during a field compation control test: weight of compacted soil excavated from pit = 510gm; bulk unit weight of sand (determined separately) = 1.46g/cc; weight of sand required to fill the pit = 425g; compute the dry unit weight of the fill.

Discuss coefficient of consolidation and degree of consolidation.

A 20mm thick specimen of clay takes 20minutes to reach 50% consolidation in the laboratory when drained both ways. if the coefficient of volume compressibility is 2.5×10^-4 m²/kN, solve for the coefficient of consolidation and coefficient of permeability of the soil.

Distinguish between direct shear test and triaxial shear test.

A sample of cohesoinless sand in a direst shear test fails under a shear tear stress of 160kpa when the normal stress was 240kpa. Predict the angle of shearing resistance of the sand. Find the principal stress and locate the principal planes.