- 7 5 M 8 M 7 B C Impermeable Stratum I D 8 M A Figure Q1c C Consider The Flownet In The Figure Q1c With Flow Undernea 1 (22.19 KiB) Viewed 25 times
7.5 m 8 m 7 B C Impermeable stratum I D 8 m A Figure Q1c
(c) Consider the flownet in the Figure Q1c, with flow underneath the impermeable dam. (i) Estimate the flow rate (q) below the dam if the permeability of sand is 3.5 × 10-5 m/s. (2 marks) (ii) Estimate the effective vertical stress and pore water pressure at Points A and B, if the saturated unit weight of the sand is 19 kN/m³. (4 marks) (iii) Estimate the uplift pressure at Point C below the dam. (2 marks) (iv) If a borehole is drilled at Point A, what would be the difference in water level (H) between the borehole and the downstream water surface? (2 marks) (v) Derive the expression for critical hydraulic gradient (ic) for quick condition, and explain why the value of ic is usually close to 1.0. (5 marks)