A sample of soil taken at a depth of 5 m in a homogeneous over consolidated saturated clay was testedunder standard triaxial CU conditions. Its water content was 48%. The soil was isotropically consolidated to a mean effective stress of 50 kPa and then unloaded to a mean effective stress of 15 kPa. The peak deviatoric stress reported by the soil technician is 20 kPa. The critical state friction angle is 32°. A one-dimensional consolidation test gave the following results: Cc = 0.32, Cr = 0.06, and OCR = 6. In the field, the groundwater level is at the ground surface.
(a) Is the reported peak deviatoric stress reasonable?
(b) Is the CU test, as conducted, representative of the in situ conditions? Justify your answer.
(c) Estimate the undrained shear strength of the in situ soil sample.