Two CD triaxial tests are conducted on identical specimens of the same sand. Both specimen...

Two CD triaxial tests are conducted on identical specimens of the same sand. Both specimens are initially consolidated hydrostatically to 50 kPa; then each specimen is loaded as shown in Fig. Specimen A failed when the applied Δσ1 was 180 kPa. Make the necessary calculations to

(a) plot the Mohr circles at failure for both tests, and (b) determine ϕ’ for the sand. (After C.W. Lovell.)