A dam shown in Figure Q1 (c) retains 6m of water. A sheet pile wall on the upstream side (which is to reduce seepage under the dam) penetrates 4m into a 10m thick of silty sand stratum. Below the silty sand is a thick deposit of clay. Assume that the silty sand is homogeneous and isotropic.
(c) A dam shown in Figure Q1 (c) retains 6m of water. A sheet pile wall on the upstream
side (which is to reduce seepage under the dam) penetrates 4m into a 10m thick of silty
sand stratum. Below the silty sand is a thick deposit of clay. Assume that the silty sand
is homogeneous and isotropic.
(i) Calculate q in cm/s.(ii) Analyze the pore water pressure distribution on the front of the sheet pile (at
every 2m @ at points A, F and G). Given the Nd of points A, F and G are 0.5,
1.5 and 3.0 respectively.
(iii) Analyze the pore water pressure distribution at the base of the dam. (at every
5m @ at points A, B, C, D and E). Given the Nd of points A, B, C, D and E are
5.6, 6.7, 8.0, 10.0, 13.0 respectively.
(iv) Determine the uplift force under the dam.
(v) Calculate the factor of safety against piping. Given Lmin = 0.85m.
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