A soil profile shown in figure below.

a$)$ Find the amount of consolidation settlement.

$($Nomnally consolidated$)$

b$)$ If the coefficient of consolidation of a clay layer is $0\mathrm{.}0018c\frac{m^2}{sec},$ how long dose it take for $60\%$ of consolidation to accour and how much would be the settlement at this time.

$C_c=0\mathrm{.}009(LL-10)$

$P=48k\frac{N}{m^2},H_1=7m,H_2=5\mathrm{.}1m,H_3=2\mathrm{.}4m$

Sand $,{}_{\text{d}\text{r}\text{y}}=17\mathrm{.}3k\frac{N}{m^3},{}_{\text{s}\text{a}\text{t}}=18\mathrm{.}1k\frac{N}{m^3}$

Clay

${}_{\text{s}\text{a}\text{t}}=18\mathrm{.}9k\frac{N}{m^3},LL=50$

$e=0\mathrm{.}9$

Sand