Mechanical Behavior of Marine Clay Under Wave Loading

摘要

The mechanical behavior of marine clay under wave loading plays a significant role in the stability of offshore structures. A series of cyclic triaxial tests and cyclic simple shear tests was conducted on marine clays from Tianjin Port, China. The effects of loading frequency as well as stress and strain amplitudes on the degradation of cyclic shear modulus of marine clay were investigated. A piezoelectric bender element system was developed to measure the maximum shear modulus of clay samples under different confining pressures. The cyclic triaxial tests show there exists a threshold shear stress for marine clays, and when the cyclic load is smaller than the threshold the soil sample will not fail, and when the cyclic load is larger than the threshold the shear modulus will continuously decrease until failure. When the stress amplitudes of the cyclic load are identical, the decrease of loading frequency leads to an increase in the accumulated shear strain and pore pressure with respect to the number of cycles. The strain-controlled cyclic simple shear tests show the degradation of the shear modulus occurs during the initial stage of loading, and the number of loading cycles has little effect on the damping ratio.