Explain at least two differences between Shear Stress controlled and Strain controlled direct shear tests.

At what water content is the sample for direct shear test prepared and how much water is to be used to prepare the sample for this test.

At what state of saturation is the sample tested and why?

Explain on the two types of sand sample preparation for Shear Box. Distinguish the differences that could be obtained from the test results. Also discuss on the dilation of the sand that could be obtained from the test results.

Determine the value of the apparent cohesion that would be expected from an unconfined compression test on the same soil.

A drained triaxial test was conducted with the same soil at a chamber pressure of $70$kPa. Determine

$($a$)$ Deviator stress at failure

$($b$)$ Angle that the failure plane makes with the major principal plane.

$($c$)$ The normal and shear stress at failure on a plane which makes an angle of $30$ degrees with major principal plane. Also explain why the specimen did not fail along this plane during the test.