As part of a construction project, a 7.5 m thick layer of clay is to be loaded with a temporary 3 m thick sand layer (refer to Fig. P8.32). The figure shows the water-table location, soil unit weights, and the compression curve properties for the clay. Assume the sand layer remains dry.

(a) Calculate the value of σ'v in the middle of the clay layer (at 3.75 m below the water table) before the sand layer is applied, and after consolidation is complete.

(b) Based on your answer in part (a), and the compression curve characteristics, calculate the settlement that will occur under these conditions.

(c) How much will the clay layer heave when the 3 m sand layer is removed?

3 m Applied sand layer, y = 16 kN/m3 Clay, Y = 20.5 kN/m o, = 74 kPa, C, = C = 0.03, C = 0.18 7.5 m