Geotechnical Engineering — Summer 2021

Demonstrate one dimensional consolidation phenomenon with spring analogy.

Critically differentiate between Rankine’s and Coulomb’s earth pressure theories.

Draw a neat sketch and explain three phase diagram. With the help of diagram, prove n = e/(1+e)

What is safe bearing capacity?

Asoil layer settles by 50 cm in 50 years under double drainage condition. what will the time period for the same settlement if a sand layer introduced at the center of the clay layer?

Draw the active earth pressure diagram for retaining wall shown below. q= 10 kN/m2 H = 6 m; φ =200, c=25 kN/m2,1 γ =18 kN/m3 H = 3 m; φ =350, c=0, γ =20 kN/m32

Draw the passive earth pressure diagram for retaining wall shown above.

What is quick sand?

Derive an equation for factor of safety of infinite dry soil slope.1

Determine the ratio of the vertical to the horizontal permeability of the soil. Also determine the resultant permeability for soil strata. H = 2 m; k =2×10-3 m/day11 H = 3 m; k =2×10-8 m/day22 H3 = 4 m; k3 =2×10-3 mm/day H = 6 m; k =2×10-4 m/day44

1 kg of soil has water content of 10% and void ratio of 0.5 at natural state. Determine water content added to get 100% saturation. Specific gravity of soil is 2.60.

Derive an equation for coefficient of earth pressure at rest condition.

Draw the Mohr’s circle for soil elements shown below, and locate the position of pole.

How is consolidation different from soil compaction?

Enlist various compaction instruments used in field. Specify their suitability for different soils.

Classify the soils A, B, Cand D, following the Indian Standard. Soil Bconsists of silt and coarse soil. For Soil D, the liquid and plastic limits are determined to be 50% and 20%, respectively.2

Classify the circular slope failure based on depth factor.

Enlist factor affecting permeability of soil. Explain any two in detail.

What are advantages of tri-axial test over direct shear test. Classify tri-axial compression tests based on drainage conditions.

What are assumptions made in Terzaghi’s theory of one-dimensional consolidation.

Describe Proctor and modified Proctor tests.

Write short note on any four: Direct shear test Factors of safety Bearing capacity Mohr-coulomb theory Boussinesq’s theory

The specific gravity and void ratio of soil is measured to be 2.65 and 1, respectively. Determine seepage velocity if the discharge velocity is 0.003 m/day.

Explain the method to determine the pre-consolidation pressure.

Write short note on any four: Proctor test Sensitivity of soil Mohs’s theory Flow net Vane shear test3