CIVL 210 Soil Mechanics I SAMPLE FINAL EXAM

CIVL 210 Soil Mechanics I SAMPLE FINAL EXAM CIVL 210 { Soil Mechanics I SAMPLE FINAL EXAM FOPR 363lCIVL 210 (Section 202) Final Examination-April 2003 Page 2 Student Name: Student Number: SECTION A 5 Questions (1-114Hours) Marks Question 1 Sampling of a seabed deposit, 80 m below sea level, shows it to be a uniform sand with a saturated unit weight of l 8 k ~ l m ~ . Hydrostatic groundwater conditions exist in the sand. [5] (a) Calculate the effective vertical stress at a depth of lorn below the seabed. A consolidated-drained (CD) triaxial test (cell pressure = 100kPa,deviator stress at failure = 200 kPa) yields the Mohr diagram shown in Figure 1. [5] (b) Determine the angle of shearing resistance of the sand (4). [5] (c) Calculate the shear strength along a horizontal plane at a depth of 10m below the seabed. d c b Figure 1- Mohr Circle Figure 2 - Seepage Conditions Question 2 For the condition of 1-D seepage illustrated in Figure 2, and the given datum, calculate: [9] (a) The pressure head, the elevation head and the total head at point D in the soil. [6] (b) The effective stress at point E in the soil. SAMPLE SHORT QUESTIONS: 2 FOPR 363lCIVL 210 (Section 202) Student Name: Final Examination- April 2003 Student Number: Page 3 Marks Question 3 With regard to the undrained shear strength of fine-grained soils: (61 (a) Explain the term sensitivity. With regard to the strength of loose, saturated sands: [9] (b) Explain the groundwater conditions and associated stress regime that result in quicksand. Question 4 A concrete dam (Figure 3a), founded on an anisotropic soil, incorporates a 4.6 m cut-off sheet pile to control seepage. The condition of 2-D seepage yields the transformed flow net (Figure 3b). The horizontal and vertical permeability are, respectively, 1.6x10-~m/s and 1x1~ - ~ m / s . [6] (a) Confirm the scale of the transformed flow net is correct. [9] (b) Calculate the hydraulic gradient across the zone of horizontal flow beneath the dam represented by points A and B on the transformed flow net.