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$($e$)$ Is the clay normally consolidated or overconsolidated? Provide a bricf justification! $(2$ marks$)$

$($f$)$ When the pressure exerted at the centre of the clay layer increased from $50$kPa to $100$kPa, the void ratio reduced from $1\mathrm{.}24$ to $1\mathrm{.}15.$ The hydraulic conductivity of the clay layer was determined as $k=5\mathrm{.}5{10}^{-7}c\frac{m}{sec}.$ Calculate the time required for the layer to reach $50\%$ consolidation. $(6$ marks$)$

$($g$)$ Determine the settlement when it reaches $50\%$ consolidation. $(2$ marks$)$

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Figure $3$

Question $5(25$ marks$)$

Part A $(8$ marks$)$:

A normally consolidated clay soil has angle of friction values $=20$ and ${}^{\text{'}}=28,$ measured respectively under total and effective stress conditions. If a consolidated$-$undrained test is conducted on this clay with an all around pressure of ${}_3=148\mathrm{.}35$kPa, what will be the major principal stress, ${}_1,$ and the pore water pressure, $u,$ at failure conditions?

Part B $(17$ marks$)$:

Consolidated$-$Undrained $($CU$)$ tests are conducted on identical soil specimens. The samples were saturated prior to the shearing process. Table $3$ shows the results for three of the samples;