Question $7$

In the linear elastic perfectly plastic behaviour... $($only one statement is correct$)$

A$)$ both the stiffness and the vield stress are infinite

B$)-$ the pre$-$yielding stiffness is constant and the yield stress remains constant after yielding is attained

C$)$ the stiffness is constant and the vield stress is infinite

D$)$ the pre yielding stiffness is zero and the yield stress remains constant after yielding is attained

E$)...$the pre$-$yielding stiffness is infinite and the vield stress remains constant after yielding is attained

Questian $8$

During the deviatoric phase of a triaxial consolidated undrained $($CIU$)$ test on a normally consolidated clay specin one statement is correct$)$

A$)...$ the contracting$/$dilating behaviour depends on the initial value of the void ratio

B$)$ positive $($contraction$)$ volumetric strains develop as the deviator stress increases

C$)$ negative $($dilation$)$ volumetric strains develop as the deviator stress increases

D$)$ positive excass pore water pressures develop as the deviator stress increases

E$)...$negative excess pore water pressures develop as the deviator stress increases

Question $1r=22m$ below the ground surface. The ground water table $(gw.t$ is at a depth $r=17m$ below the ground surface.

A$){}_{10}=257\mathrm{.}6$kPa

$){}_{no}=290$kPa

C$){}_{\text{n}\text{o}\text{t}}=240$kPa

D$){}_{he}=210$kPa

E$){}_{mo}=260$kPa

Points: $2\mathrm{.}5$

Question $2$

According to the definition, the invariants of the stress state are mathematical entities that...$($only one statement is correct$)$

A$)$ identify the maximum normal stresses of the point

B$)$ identify the stress state on the horizontal and vertical planes

C$)$ are independent of the mean stress

D$)$ are independent of the reference system

E$)$ are independent of the stress path

Points: $2\mathrm{.}5$

Question $3$

Let: Vetotal volume; $V_3=$ volume of solids; $V_4=$volume of voids; $V_w=$ volume of pore water. What is the general definition of the porosity $(n)?$

A$)n=V_{v}N$

B$)n=V_i{N}_w$

C$)n=v\frac{v}{V_v}$