Post-Cyclic Undrained Behavior of Compacted Composite Clay Subjected to Various Cyclic Loading Paths

Abstract

Using a sequential procedure of undrained cyclic and post cyclic tests, the strength and stiffness degradation characteristics of compacted composite clays are studied immediately after various cyclic loading paths by triaxial and hollow cylinder tests. The effects of cyclic loading paths, sand contents, cyclic loading amplitude and confining pressure on the post-cyclic mechanical behavior of the composite clays are evaluated. The results point out different peculiarities which can be of interest in assessing the mechanical behavior of the composite clays under post seismic shaking. The results show that effect of cyclic loading on post cyclic pore water pressure build-up is significant when pore water pressure build-up is considerably lower than the associated value in monotonic loading. The effect of sand content and cyclic loading path on degradation of stiffness is more remarkable than shear strength. Test results also reveal that the effect of sand content on the post cyclic pore water pressure build-up is minor. However, when the aggregate content increases the shear strength increases.