Effects of initial static shear stress on post-cyclic degradation of a plastic silt

Post-cyclic degradations in strength and stiffness of a reconstituted plastic silt were investigated using triaxial tests with special reference to the effect of initial sustained shear stress. The results from a series of tests revealed that : (1) As found previously for the case of no initial stress, the cyclically induced degradation of the secant modulus is more marked than that for undrained strength. 2) Degradations in undrained strength and secant modulus of a plastic silt with an initial shear stress can be predicted as a function of cyclic-induced excess pore pressures using the methods which were previously proposed for cohesive soils with no initial shear stress.