SOME MECHANICAL CHARACTERISTICS OF SOFT CLAY UNDER CYCLIC AXIAl SHEARING

The mechanical characteristics on the deformation, pore pressure and shear strength of undisturbed soft clay samples are studied with cyclic axial shear tests. The effects of confining pressure, cyclic stress ratio, frequency of cyclic loading and cyclic numbers are considered. The study results show that the pore pressure and axial strain took on a fluctuant increasing process under cyclic shear loading. The amplitudes of pore pressure increased notably with the increase of cyclic stress ratio, and the residual pore pressure also increased obviously. In the meantime, the pore pressure also increased with the increase of confining pressure. More cyclic numbers were needed under a high frequency of cyclic loading than a low frequency of cyclic loading in order that the residual pore pressure could achieve the same value. However, the effect of frequency was not obvious with the increase of cyclic numbers.