NUMERICAL ANALYSES OF DYNAMIC RESPONSE OF VISCO-ELASTIC SEABED UNDER WAVE LOADING

Based on generalized Biot's theory, the u～U finite element formulations for dynamics of seabed under wave loading are derived by applying Galerkin's weighted-residual procedure, where u and U are the displacements of soil matrix and porous fluid respectively. The Kelvin-Voigt visco-elastic model is used to reproduce the constitutive relationship of seabed soils. The governing equations are numerically solved by Newmark's time integration scheme. Numerical results show that the accelerations of soil matrix and porous fluid have little effect on the dynamic response of visco-elastic seabed. When the value of viscosity coefficients is less than that of elastic shear modulus, the amplitudes of pore pressure change slightly with the variation of the viscosity coefficients and the viscosity coefficients affect the amplitudes of effective stresses considerably. For the seabed with large viscosity coefficients, wave loading induces monotonically increasing shear strains and the soil may reach failure state in short time.