A buried clay layer 10 ft thick is sandwiched between strata of free-draining granular soil so that double drainage during consolidation can occur. Calculations indicate that, because of a planned...

A buried clay layer 10 ft thick is sandwiched between strata of free-draining granular soil so that double drainage during consolidation can occur. Calculations indicate that, because of a planned building loading, an ultimate settlement of 2 in. is expected as a result of primary compression in the clay layer. The coefficient of consolidation for the clay is 0.01 ft²/day.

(a) How long will it take for 90 percent of the estimated settlement to take place?

(b) How much settlement will occur in one year?

(c) How long will it take for 1 in. of settlement to take place?