Two CU triaxial tests are performed on a clay specimen. At failure, the results are: Test 1: σ3 = 30 kPa, P = 0.45 kN, Area of specimen = 0.01 m2 , u = 10 kPa Test 2: σ3 = 60 kPa, P = 0.70 kN, Area of specimen = 0.01 m2 , u = 20 kPa a) Find σ1, σ3, σ'1, and σ'3 at failure for both tests. b) Draw the effective stress Mohr's circle for both tests and draw the Mohr-Coulomb failure envelope for the clay. What are ' and c' for the clay? Write the equation for the MohrCoulomb failure envelope.

In a unit cell of fcc structure, indicate the position of one of the tetrahedral interstitial sites by plotting the corresponding tetrahedron. do the same for one of the octahedral interstitial sites (in a separate fcc unit cell). mark the positions of all the tetrahedral and octahedral interstitial sites in the unit cells. how many equivalent tetrahedral sites and how many equivalent octahedral sites are contained in a fcc unit cell, respectively. what is the coordination number for a tetrahedral site and what is the coordination number for an octahedral site?