2. Figure 2 shows a concrete dam with sheet piles underneath with flow net drawn. The dam base is 0.4 m below the soil surface (d = ds dc dp de dr = ds = 0.4 m). The upstream water level is 3.5 m above the soil surface and the downstream water level is at the soil surface. The soil above the impervious layer is 5.5 m deep, and its permeability k = 1 x 109 m/s. Saturated unit weight of soil = 17 kN/m Calculate (a) Flow rate beneath the dam from upstream to downstream for a 1 m run into the page in m/year/m; (q=3.40 x 10 m/year/m) (b) Pore pressures at points A, B, C, D, E, F and G at the base of the dam; (using g = 9.81 m/s, UA = 22.0 kPa; us = 20.2 kPa; uc = 17.5 kPa; up=14.8 kPa; us = 12.1 kPa; u = 9.38 kPa; uc = 6.69 kPa) (c) The magnitude of total hydraulic force acting at the base of the dam for a 1 m run into the page (between points A and G); (F = 132.8 kN/m) (d) Effective stresses at points H and I; (o' = 6.0 kPa; ' = 17.5 kPa) 1.2m 1.1m 2m 2.1m 1.2m 0.8m D E FG d=1.2m d = = 2.8m ' ' Ho=3.5m d = 0.4m -2.3m A B d = 5.5m Impervious layer