Assume that the compressible soil shown in Figure 1 consists of a clay layer 10 ft thick. A laboratory ocdometer test made on a sample from the center of the layer indicates the following: Initial void ratio, e, = 1.10, Saturated density, y= 115 Ib/f Existing overburden pressure p, = 0.7 tons/ft Pre-consolidation pressure, P. = 2.2 tons/ft? Laboratory compression index C, = 0.35 Swelling index C, = 0.06. Calculate the settlement of the surface of the upper incompressible layer due to the imposition of a uniform surcharge pressure of 5.0 tons/ft2. Uniform Vertical Surcharge Pressure

The laboratory consolidation data for an undisturbed clay specimen are as follows: e1 = 1.12 P₁ = 90 kPa e2 = 0.90 P2 = 450 kPa 1. Compute the value of the compression index. 2. Compute the value of the swell index assuming it is equal to 1/6 the value of the compression index. 3. Compute the void ratio for a pressure of 600 kPa. 4. Compute the coefficient of compressibility. 5. Compute the value of the coefficient of volume compressibility.

Below are results from three unconsolidated undrained triaxial tests performed on a fully saturated clay specimen: Test No. 1 2 Minor principal stress (psi) Major principal stress at failure (psi) 10 25 33 22 37 45 Moisture content = 21 % Determine: a) Void ratio (e) of the soil. You may use eS = wG_ (assume Gs = 2.70) %3D b) Deviatory stress at failure for each test trial c) Shear strength parameters (cu and ø). Hint: Sketch the Mohr's circles for the three trials. 3.

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A CU triaxial test was carried out on a silty clay that was isotopically consolidated using a cell pressure of 125 kPa. The following data were obtained: Axial load (kPa) 0 5.5 11.0 24.5 28.5 35.0 50.5 85.0 105.0 120.8 Axial strain, &₁ (%) 0 0.05 0.12 0.29 0.38 0.56 1.08 2.43 4.02 9.15 Au (kPa) 0 4.0 8.6 19.1 29.3 34.8 41.0 49.7 55.8 59.0 (a) Plot the deviatoric stress vs. axial strain and excess porewater pressure vs. axial strain, respectively. (b) Determine the undrained shear strength (sµ). (Note: we assume that the sample reaches failure). (c) Determine the total principal stresses (0₁,03) and the effective principal stresses (0₁, 03') at the failure, respectively.

The consolidation test of a clay sample taken from a 2 m thick normally consolidated clay soil layer has been conducted and the results are shown in the table below. The average overburden stress of the clay soil layer is 50 kPa, What would the total settlement (mm) be if an additional 100 kPa loading is applied over a large area on the top of the clay layer? (Hint: void ratio is related to the sample volume) P(kPa) 0 50 100 200 400 e 0.850 0.760 0.710 0.650 0.640

Refer to Figure 11.41. Given that B =1 m, L = 3 m, and Q = 110 kN, the soil characteristics given in the figure are Cs = 1/5 Cc, Ꝺ’c= 40 kN/m2. Field monitoring indicated that the foundation settlement was 19 mm during the first 12 months. a. Estimate the average stress increase in the clay layer due to the applied load. b. Estimate the primary consolidation settlement. c. What is the degree of consolidation after 12 months? d. Estimate the coefficient of consolidation for the pressure range. e. Estimate the settlement in 24 months. Answer must be: A. 6.33 B. 32.82 C. 57.89 D. 0.0013 E. 25.66

For a normally consolidated soil, the following is given: Determine the following: a. The compression index, Cc. b. The void ratio corresponding to pressure of 200 kN/m2

‹ample 9.1: Following results were recorded from a consolidation test on a specime turated clay, each load being maintained constant for 24 hours before the addition o ext increment.

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