Question $6$:

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

The results in Table $1$ given below were obtained at failure conditions in a series of

consolidated$-$undrained triaxial tests with pore water pressure measurements on fully

saturated clay specimens. Determine the effective shear strength parameters $($i$.$e$,$ c$\text{'}$ and

b$)$ for the tested soil. If a specimen of the same soil were consolidated under a confining

stress, ${}_3$ of $250$ kPa $,$ what would be the expected value of the principal stress difference

at failure?

Table $1$

Answer the questions given below based on the results you have obtained.

$($i$)$ Is the clay normally consolidated or over consolidated? Give reasons

$($ii$)$ If an earth dam is constructed using this clay, can you use the above shear

strength parameters to determine the short term stability of the structure

Give reasons