Question $2$:

$2.$ A CD triaxial test is conducted on a sample of sand from Ft$.$ Peck Dam, Montana. The initial area of the specimen was $\backslash (10\backslash$mathrm$\{$~cm$\}^\{2\}\backslash )$ and the initial height was $70$ mm $.$ Initial void ratio was $0\mathrm{.}605.$ The data in table $2$ were collected during shear.

a$.$ Calculate and plot axial stress vs$.$ axial strain and volumetric strain vs$.$ axial strain.

b$.$ Draw the Mohr circle representing the state of stress at failure. Assuming cohesion is zero, what is the peak friction angle based on the test.

c$.$ Determine the orientations of the failure planes and the magnitudes of the normal and shear stress acting on the failure planes at failure. Draw a simple diagram to illustrate your answer.

Table $2$: Consolidated Drained Triaxial Test Results