Example 5.11 A clay stratum 8.0 m thick is located at a depth of 6 m from the ground surface. The natural moisture content of the clay is 56% and G
s = 2.75. The soil stratum between the ground surface and
the clay consists of fine sand. The water table is located at a depth of 2 m below the ground surface. The submerged unit weight of fine sand is 10.5 kN/m3, and its moist unit weight above the water table is 18.68 kN/m3• Calculate the effective stress at the center of the clay layer.