$($a$)$ Three clay samples from the same layer were tested using a

soil triaxial cell Consolidated Undrained test with Pore

Pressure measurement. The results at failure are given in

Table $1.$ Determine, by graphical methods, the effective

stress parameters $c^{\text{'}}$ and ${}^{\text{'}}$ for this particular clay.

Table $1.$ Triaxial Test data.

$($b$)$ How does the shear stress at failure $()$ differ between fine

grained $($clay$)$ tailings and coarse grained $($sand$)$ tailings?

$($c$)$ Define the theory of effective stress, and explain why it

controls the strength and the volume of tailings.

$($d$)$ Explain what type of triaxial test is best for cohesive tailings

samples, and what parameter would be calculated during

this test.