A large oil storage tank 90 m in diameter is to be constructed on the soil profile shown in Fig. P10.16. Average depth of the oil in the tank is 18 m, and the specific gravity of the oil is 0.92. Consolidation tests from the clay layer are similar to those given in Problem 8.18. Estimate the maximum total and differential consolidation settlement of the tank. Neglect any settlements in the sand. Work this problem:

(a) Assuming conditions at the mid-depth of the clay are typical of the entire clay layer.

(b) Dividing the clay layer into four or five thinner layers, computing the settlement of each thin layer and summing up by Eq. (8.14). Hint: See Example 10.8.

Depth (m) 2 m - 10 Dense sand Psat = 1.81 Mg/m3 -20 Medium stiff clay w, = 29.3% e, = 0.79 Pa = 1.5 Mg/m3 -30 -40 - Sand