A stress$-$controlled compression test is carried out on a sample of

normally compressed clay with a total confining stress of $490$kPa,

which is held constant throughout the test. Each load increment

is left on for sufficient time to allow the sample to reach a new

state of equilibrium, as recorded in the table below. For the first

three increments $AB,BC,$ and $CD,$ the sample is undrained. The

drainage connection is then opened, and the sample reaches

equilibrium again at E$.$ Further load increments are applied, with

drainage allowed, until the sample reaches failure at $F,$ and the

sample is then in a critical state.

Plot the progress of the test in the $p^{\text{'}}$:$q$ effective stress plane and

in the $p^{\text{'}}$:$v$ compression plane and estimate the position of the

critical state line for this clay.

Two additional samples of this clay $(x$ and $Y)$ are normally

compressed under an isotropic pressure $p^{\text{'}}=350$kPa. If a con$-$

ventional drained triaxial compression test is performed on $x,$

predict the values of $p^{\text{'}},q,$ and $v$ at failure. If a conventional

undrained triaxial compression test is performed on $Y,$ predict the

values of $p^{\text{'}},u,$ and $q$ at failure.

$q($kPa$)u($kPa$)v$

A $002\mathrm{.}270$

B $39\mathrm{.}228\mathrm{.}02\mathrm{.}270$

C $78\mathrm{.}470\mathrm{.}02\mathrm{.}270$

D $154\mathrm{.}0200\mathrm{.}92\mathrm{.}270$

E $154\mathrm{.}002\mathrm{.}205$

F $623\mathrm{.}001\mathrm{.}990$

This question form Soil Behavior and Critical State Soil Mechanics Book in p$\mathrm{.}173-174($Authur : David Muir Wood.$)$