Question $6(10$ marks$)$

A $4$ m thick layer of sandy gravel alluvial deposit is underlain by saturated normally consolidated clay, as shown in the Figure below. A clay sample was extracted from a depth of $9$ m below the ground surface, where laboratory tests indicate the following soil characteristics:

Coefficient of earth pressure at rest $K_0=0\mathrm{.}7$

Pore pressure parameters: $A=0\mathrm{.}65,B=1$

Estimate the pore pressure just after its removal from the ground.

$(10$ marks$)$