Question

Two triaxial compression tests are conducted on identical specimens of the same saturated clay. In the first test the soil is first consolidated to sc=350 kPa and u0=200 kPa and then sheared under drained conditions increasing the axial stress while keeping the chamber pressure constant. At failure s1= 560 kPa. In the second test, the specimen is consolidated to sc=600 kPa and u0=400 kPa, then it is sheared under undrained conditions increasing the axial stress while keeping the chamber pressure constant. At failure (s1-s3)=130 and the excess pore pressure Du=107 kPa. Draw the total and effective Mohr circles at failure for the two specimens and determine the Mohr-Coulomb strength parameters (c’ and f’). Do you believe this clay is normally or overconsolidated?

Answer 1