The bed of a lake consists of a deposit of silty sand with a void ratio...

 

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The bed of a lake consists of a deposit of silty sand with a void ratio of e = 0.6 and a coefficient of permeability of k = 5 x 10 4 The depth of water in the lake is 4 m. It is known that water is seeping vertically upwards through the silty sand from an underlying aquifer. a) If it is known that water is seeping upward at the rate of 2.0 x 10-4 per square metre, what is the vertical effective stress at a point 3 m below the lake bed? b) Calculate the change in the vertical effective stress at this point if the depth of water in the lake increases to 8 m, but the rate of the upward flow remains unchanged. The bed of a lake consists of a deposit of silty sand with a void ratio of e = 0.6 and a coefficient of permeability of k = 5 x 10 4 The depth of water in the lake is 4 m. It is known that water is seeping vertically upwards through the silty sand from an underlying aquifer. a) If it is known that water is seeping upward at the rate of 2.0 x 10-4 per square metre, what is the vertical effective stress at a point 3 m below the lake bed? b) Calculate the change in the vertical effective stress at this point if the depth of water in the lake increases to 8 m, but the rate of the upward flow remains unchanged.