A standard undrained triaxial test was performed on a fi ne-grained soil. The soil was consolidated to a cell pressure of 120 kPa and then unloaded to a cell pressure of 80 kPa. The axial stress at failure (critical state) was 64 kPa. Assume Λ = 0.8.
(a) Determine the normalized undrained shear strength.
(b) Estimate ∅'cs.
(c) Estimate the undrained shear strength of the same soil if it were normally consolidated.
(d) Estimate the undrained shear strength of the same soil if it were to be subjected to direct simple shear.
(e) Recommend the undrained shear strength for use in the design of (1) a foundation for an oil tank, and (2) a slope.