Laboratory Measurements of the Dynamic Properties of Shanghai Clay

Abstract

It is well agreed that the dynamic properties including the dynamic shear modulus and damping ratio play essential role in many dynamic geotechnical problems. In this paper, the dynamic properties of the typical Shanghai clay were determined by resonant column tests on 38 undisturbed samples obtained from 9 site investigations in Shanghai. The results showed that the dynamic small strain shear modulus G 0 of the soil significantly depends on the void ratio and the effective confining pressure. Meanwhile, the ratio of shear modulus at a certain shear strain level to the small strain shear modulus G/G 0 (i.e. modulus reduction curve) decreases and the damping ratio increases continuously as the shear strain increases, indicating the nonlinear behavior of clay under dynamic loading. Meanwhile, the modulus reduction curve and the damping curve are generally independent of the void ratio and the effective stress. Empirical equations were provided to predict the small strain shear modulus, the modulus reduction curve and damping ratio of Shanghai clay in practical engineering.