A $3\mathrm{.}75m$ clay layer in the field $($drained on one side$)$ is normally consolidated. When the pressure is increased from $50k\frac{N}{m^2}$ to $150k\frac{N}{m^2},$ the void ratio decreases from $0\mathrm{.}9$ to $0\mathrm{.}75.$ The hydraulic conductivity, $k,$ of the clay for the above loading range was found to be $6{10}^{-7}c\frac{m}{sec}.$

a$.$ How long $($in days$)$ will it take for the clay layer to reach $50\%$ consolidation?

$(20$ Points$)$

b$.$ What is the settlement at that time $($that is$,$ at $50\%$ consolidation$)?$

$(20$ Points$)$