Finite-element modeling of submarine landslide triggered by seismic loading in saturated cohesive soil deposits

Abstract

Dynamic sliding process of submarine slope is a hotspot issue in ocean geotechnical engineering. Due to the lack of the numerical simulation method which could describe the dynamic characteristics of the saturated soft clay under seismic loading, few researches are reported on the dynamic sliding process of submarine slope in saturated cohesive soil deposits. Adopting the subroutine interface technology provided by ABAQUS platform, the undrained cyclic elastoplastic constitutive model, which could describe the dynamic characteristics of saturated soft clay, is programmed into user-defined material subroutine VUMAT and embedded in display dynamics analysis module of ABAQUS platform. Based on the cyclic elastic-plastic constitutive model and the updated Lagrangian technology, a numerical simulation method is proposed to investigate the dynamic sliding process of submarine soft clay slope under seismic loading. The applicability of the proposed numerical simulation method is verified by comparing with the previous research results. The results show that the strain accumulation characteristic makes the final accumulated deformation and shear strain larger than that of the conventional numerical modeling methods. When the general static constitutive model is used for dynamic analysis of slope, the analysis results are not conservative because the strain accumulation characteristic cannot be considered. Besides, it can display the whole dynamic sliding process of the slope, more intuitively predict the slope topography before and after earthquake, which could provide a reference for the planning and design of offshore structures.