Q$5.(20$P$.)$ A soil profile consist of $xm$ of gravel overlying a clay layer of $Ym$ thickness, which in turn rests

on a $Zm$ sand layer. The drained and saturated unit weights of the gravel are $18k\frac{N}{m^3}$ and $20k\frac{N}{m^3}.$ Unit

weights of the clay and the sand are $20k\frac{N}{m^3}$ and $19k\frac{N}{m^3},$ respectively. Below sand layer lies an impermeable

bedrock. If a wide excavation of $3m$ depth is to be made in a relatively short time, draw the effective, total and

pore pressure diagrams before, immediately after and long time after excavation is made. The ground water

table is $5m$ below the ground surface and unit weight of water is $10k\frac{N}{m^3}.$ X$=8$ Y$=3$ Z$=3$