2018 NATIONAL EXAMINATIONS-December 16-CIV-A4 GEOTECHNICAL MATERIALS AND ANALYSIS Question 2: State the correct answer i

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2018 National Examinations December 16 Civ A4 Geotechnical Materials And Analysis Question 2 State The Correct Answer I 1 (63.05 KiB) Viewed 30 times

2018 NATIONAL EXAMINATIONS-December 16-CIV-A4 GEOTECHNICAL MATERIALS AND ANALYSIS Question 2: State the correct answer in your ANSWER BOOK along with the Question number and explain the reason for your answer. Have all your answers for Question 2 at one place. No mark will be awarded if reason is not provided. 1 The angle of internal friction (i.e.. d) was measured from consolidated drained (i.e., CD) tests on two soils; Soil A (well-graded sand) and Soil B (uniform sand). Which one these two soils will have a higher angle of internal friction. (i): Sample A (well-graded sand) (ii) Sample B (uniform sand) 2 Two identical soil samples C and D were consolidated to effective confining pressures of 100 and 300 kPa, respectively before undrained triaxial shear tests with pore-water pressure measurement. The pre-consolidation pressure of this soil was equal to 200 kPa. Which one of these samples, C or D will have higher pore-water pressure at failure? (ii) Sample D (tested with a (i): Sample C (tested with a confining pressure 100 kPa) confining pressure 300 kPa) 5 4 In a CD test on saturated normally consolidated clay, the sample volume during shear (i) increases (ii) remains unchanged (iii) is reduced (i) (ii) Hi Reservoir level Saturated soil Impervious Flow lines. Có hao DA: q=0 (2 x 5 = 10 marks) B Equipotential lines Boundary conditions: AB: h= Hi BC: free surface, it's location is unkown Assumed impervious Free surface and uppermost flowline D C Datum Horizontal drain Figure 1 The pore-water pressure below the flow line BC (i.e., phreatic surface) in a homogeneous earth dam is equal to negative value atmospheric pressure (i.c., pore-water pressure is equal to zero) positive value