The water table is at a depth of 6.5 ft below the ground surface. The soil is mainly consists of clay up to a depth of 13 ft from the ground and below which lies sand. The clay stratum is saturated above the water table. For Clay stratum the following information is provided: Moisture content = 30 percent Specific gravity = 2.72 For Sandy stratum the following information is provided: Moisture content = 26 percent Specific gravity = 2.64. Find: (A) The total pressure, pore pressure and effective pressure at a depth of 26 ft below the ground surface. (B) The change in the effective pressure if the water table is brought down to a level of 13 ft below the ground surface by pumping.

A soil profile consists of 6 m of coarse sand overlying 12 m of firm clay. Below the clay there is a 9m thick gravel layer. The sand is estimated to have an average dry density of 1.65 Mg/m³ over its full thickness. The clay has a dry density of 1.40 Mg/m2, and to be saturated below the water table an average saturated density of 1.85 Mg/m³ over its full thickness. The average saturated density of gravel is 2.3 Mg/m³ over its full thickness. 2) c) Assuming that the ground water table drops 4 m after a heavy drought, draw the profile with the properties of the soil and the water table d) Compute the op, Oy, u at the base of the gravel layer. e) Comment on how the effective stress would change if the water table drops after a heavy drought?