Liquefaction-induced lateral spreading characteristics of the fluvial terraces at the lower reaches of Yangtze River

Abstract

The liquefaction-induced lateral spreading of the fluvial terraces can cause tremendous physical damage to the natural and built environments in the lower reaches of Yangtze River. This paper presents an integrated nonlinear site response analyses method to characterize the large-scale lateral spreading behavior in the wide river valley of Yangtze River at the scale of several kilometers in the Abaqus/Explicit code, incorporating the main features such as the spatial variability of liquefiable deposit, the liquefaction initiation and cyclic mobility at the post liquefaction stage and the geometric nonlinearity induced by the extensively large deformation. In particular, the large-deformation behavior in the numerical model is simulated by the plasticity-based model at the element level and the arbitrary Lagrange–Euler (ALE) method at the model mesh level. The key factors influencing lateral spreading behavior are investigated, involving the ground motion characteristics, the slope angle of fluvial terraces, and the spatial variability of site condition. The numerical results indicate significant spatial variation characteristics of the lateral spreading of the fluvial terraces, triggered in the slightly inclined slope. Three generation stages of lateral spreading could be identified in the time-history curve of lateral displacement, i.e. swing stage, slip stage and creep stage, respectively. Finally, the model performance of the proposed modelling method is evaluated against the widely-used empirical formula, and the difference between each other is interpreted, which provides new insights into the mechanism of liquefaction-induced lateral spreading of the fluvial terraces in the wide river valley.