Geotechnical Engineering

a) Establish the following relationship for soil parameters e S_r = wG, where e = void ratio, w = water content, S_r = degree of saturation, G = sp. gravity of soil solid.

b) A series of tests on a sample of clay gives following properties: Liquid limit = 60% Plastic limit = 25% Natural W.C. = 50% D₆₀ = 0.0050 mm D₃₀ = 0.0026 mm D₁₀ = 0.0007 mm Calculate the following: i) Uniformity coefficient ii) Coefficient of curvature iii) Gradation of soil iv) Plasticity index v) IS soil classification as per plasticity chart vi) Consistency of soil

a) A masonry dam has previous sand foundation. Determine the maximum permissible upward gradient, if a factor of safety of 4 is required against boiling? Data given, for sand, η = 50% and sp. gravity G_s = 2.70.

b) A strata has been shown in following figure.

For subsoil condition given in this figure, plot the total, neutral and effective stress distribution upto the bottom of the clay layer, when i) Water table is 2m below the G.S. (take S_r = 50% above W.T.) ii) Water table is at ground surface

a) Explain about flow nets. Write the characteristics of flow nets.

b) What are the factors affecting the permeability of soil?

c) Explain the textural soil classification.

a) A flow net was drawn for estimating the seepage under the sheet piling. The number of flow channels N_f = 5 and number of equipotential drop N_d = 12 was estimated in the flow net. If the permeability of the sand is 5×10^-3 cm/s and saturated unit weight of sand is 20 kN/m³, what is the discharge through sand strata?

b) A footing carries a uniformly distributed load of 250 kN/m². The footing size is rectangular 2.5m × 2.0 m. Find the intensity of vertical pressure at a depth of 5.0 m below the center of the footing use equivalent point load method.

c) Write the assumptions made in Boussinesq's equation formulation for stress distribution in soil.

a) Define the compaction. How it is different from consolidation?

b) Differentiate between standard proctor test and modified proctor's test.

c) Explain the following terms: i) Zero air void line ii) Quick condition iii) Seepage pressure

a) A clay stratum is 6 m thick. Under a external loading of a building how many days would be required by this clay stratum to attain 50% of its ultimate settlement. Assume both end drainage allowed in clay strata. The coefficient of consolidation of clay soil is 50×10^-4 cm²/sec.

b) Differentiate between: i) Coefficient of consolidation and coefficient of compressibility ii) Coefficient of compression and compression index iii) Shear strength and shear stress

c) Write the assumptions made in the theory of consolidation.

a) Describe the unconfined compression test. For which type of soil this test is suitable.

b) Two undrained triaxial tests were conducted on soil specimen and they gave the following results:

Confining pressure	Failure load
150 kN/m2	500 kN/m2
300 kN/m2	800 kN/m2

Determine the value of apparent cohesion and friction angle of the soil.

कन्फाइनिग दाब	टूटने का भार
150 kN/m2	500 kN/m2
300 kN/m2	800 kN/m2

c) Explain the phenomenon of "liquefaction" is saturated fine sandy soil.

a) Write the different type of soil stabilization. Discuss briefly about cement stabilization.

b) Explain following: i) Function and application of Geosynthetics ii) Grain size distribution of soil