A 7-ft layer of clay is buried beneath a 10-ft stratum of very compact granular soil. Compact sand underlies the clay. The layer of granular soil is composed of material having a unit weight of 130...

A 7-ft layer of clay is buried beneath a 10-ft stratum of very compact granular soil. Compact sand underlies the clay. The layer of granular soil is composed of material having a unit weight of 130 psf. The clay unit weight is 105 pcf. A laboratory compression test on a sample of the clay indicates a compression index of 0.40 and a natural void ratio of 1.30. A planned building loading will cause a 550-psf stress increase at the middle of the clay layer

(a) What amount of primary compression occurs in the clay layer for the indicated conditions?

(b) How much primary compression of the clay layer would result if the groundwater table was at the ground surface (all other conditions remain the same)?

(c) How much clay layer compression would occur if the clay was an overconsolidated material, the past maximum pressure was 2,000 psf, and the C_r
value was 0.10? Assume a deep water table.