$11\mathrm{.}10$ Consider the soil profile shown in Figure $11\mathrm{.}47$ subjected to the uniformly distributed load, $,$ on the ground surface. Given: $=930l\frac{b}{f}{t}^2,H_1=4\mathrm{.}5ft,H_2=9ft,$ and $H_3=16ft.$ Soil characteristics are

Sand: ${}_d=112l\frac{b}{f}{t}^3$;${}_{\text{s}\text{a}\text{t}}=123l\frac{b}{f}{t}^3$

Clay: ${}_{\text{s}\text{a}\text{t}}=119l\frac{b}{f}{t}^3$;$LL=46$;$e=0\mathrm{.}71$;$C_s=\frac{1}{5}{C}_c$

Estimate the primary consolidation settlement of the clay if

a$.$ The clay is normally consolidated

b$.$ The preconsolidation pressure, ${}_c^{\text{'}}=2100l\frac{b}{f}{t}^2$

Sand

Clay

Figure $11\mathrm{.}47$