Question $5$:

$($Value: $20$ marks$)$

A consolidated undrained $($CU$)$ triaxial test was conducted on a clayey specimen with a

confining pressure, ${}_3$ of $100$kPa. The deviator stress, $({}_1-{}_3)$ at failure condition was

measured to be equal to $60$kPa. The pore$-$water pressure, $u_w$ was also measured for this

specimen. The shear strength parameters determined from consolidated drained $($CD$)$

triaxial tests on identical specimens of the same soil are $c^{\text{'}}=0$kPa and ${}^{\text{'}}=30$ and from

consolidated undrained $($CU$)$ triaxial tests are $c=0$kPa and $=13\mathrm{.}3.$ Based on this

information, what is the corresponding pore$-$water pressure that was measured in the CU

test at a confining pressure of $100$kPa. What are the pore pressure coefficients A and $B$

for the tested specimen? Is this clay normally consolidated or over$-$consolidated? Give at

least three reasons to justify whether the clay is normally consolidated or over

consolidated.