$5\mathrm{.}8$ In a triaxial test, a soil specimen is allowed to consolidate fully under an all$-$round pressure of

$200$ kPa $.$ Under undrained conditions the all$-$round pressure is increased to $350$ kPa $,$ the pore water

pressure then being measured as $144$ kPa $.$ Axial load is then applied under undrained conditions

until failure takes place, the following results being obtained.

TABLE Q

Determine the value of the pore pressure coefficient $B$ and determine whether the test can be

considered as saturated. Plot the stress$-$strain $(q-{}_s)$ curve for the test, and hence determine the shear

modulus $($stiffness$)$ of the soil at each stage of loading. Draw also the stress paths $($total and

effective$)$ for the test and estimate the critical state friction angle.