In this paper, a combined theoretical-numerical study on dynamic response of sandy seabed soil focusing on nonlinear dynamic soil constitutive behavior is presented. First part presents a rigorous theoretical study to evaluate the cyclic behavior of seabed using the framework of bounding surface plasticity. Focus here is on more effectively modeling the elemental response, particularly liquefaction. A new hardening law is proposed to incorporate into the modified bounding surface model which is found to be the effective formulation addressing the wave-induced nonlinear seabed behavior. Second part presents a number of cyclic triaxial tests simulated to verify the new constitutive formulation. In the third part, a poro-elasto-plastic numerical model in terms of the extended nonlinear finite element form of the discretized coupled flow-deformation equations (Biot poroelasticity coupled with a constitutive model) is developed. Then, free-field wave-induced dynamic response of sandy seabed is evaluated on various problems presenting the capability of the proposed constitutive formulation in capturing residual liquefaction.

Details can be found here: doi.org/10.1016/j.oceaneng.2020.108348