Cyclic characterization of wave-induced oscillatory and residual response of liquefiable seabed

摘要

Abstract The paper presents a robust modeling method for a fully coupled effective stress analysis of the wave-induced liquefaction scenarios, based on the Biot consolidation theory. In this context, emphasis is placed on the implementation of a well-calibrated cyclic soil model and an empirical shear-volume coupling equation, which links the increment of volumetric strain per cycle of wave with the shear strain occurring during that particular cycle. Unlike most of the previous investigations using the amplitude of shear stress over the wave period (or the phase-resolved oscillatory shear stresses) as the source term for calculating the residual pore pressure, in this study, the source term is related to the rate of plastic volumetric deformation and implemented into the Biot consolidation equation to consider both generation and partial dissipation of excess pore pressure during wave propagation. Then, the proposed modeling method is incorporated into a dynamic finite difference analysis procedure. Model calibrations are carried out in terms of individual soil element behavior and seabed response under progressive waves, respectively. Overall good agreement demonstrates the reliability of the modeling method for the prediction of wave-induced seabed response. Finally, the paper highlights the potentials of proposed modeling framework to simulate the basic features of wave-induced seabed response (i.e., the coupling of progressive buildup of pore pressure and cyclic softening of soil skeleton), by means of numerical examples. The obtained results show that the cyclic behavior of liquefiable seabed under wave actions can be well captured by the proposed model. Highlights ? A cyclic characterization method of wave-induced response of liquefiable seabed is presented. ? The source term related to the rate of volumetric compaction is defined within the Biot equation. ? Model calibrations are carried out in terms of single element behavior and seabed response. ? Typical results on the cyclic behavior of liquefiable seabed under wave actions are shown. ]]>