Numerical investigation of the effects of geometric and seismic parameters on liquefaction-induced lateral spreading

摘要

The lateral movement of a liquefiable soil layer on gentle slopes is the most visible and devastating type of liquefaction-induced ground failure. Recent earthquakes have shown that this phenomenon causes severe damages to coastal structures, pier of the bridges and life-lines by exerting large lateral forces on the structures. In this paper coupled dynamic field equations of extended Biot's theory with u-p formulation are used for simulating the phenomenon and the soil behavior is modeled by a critical state two-surface plasticity model for sands. Furthermore, in this study variation of permeability coefficient during liquefaction is taken into account. The permeability coefficient is related to variation of the excess pore water pressure ratio. At first, two centrifuge tests on liquefiable sand which have gently inclined ground surfaces with different conditions are simulated and numerical results are compared with experimental observations. These comparisons showed that numerical simulations have very good consistency with experimental observations in modeling of excess pore pressures, lateral displacements, and surface settlements. After validation, the effects of different factors such as ground slope, thickness of the liquefiable layer, soil relative density, maximum acceleration of dynamic loading, frequency of input motion and number of load cycles are investigated on the amount of lateral displacement. At the end, by using the results of the conducted extensive parametric study, a new relation is proposed for estimating the magnitude of maximum lateral displacement. Comparison of the results of this equation with experimental records, field observations and other empirical relations shows the advantage of this equation over other previously proposed relations. (C) 2016 Elsevier Ltd. All rights reserved.