Efficient Numerical Modeling of Liquefaction-Induced Deformations of Soil Structures

A new numerical methodology is presented for the simulation of the non cohesive soil response under small, medium and large cyclic shear strains, with special interest given to liquefaction phenomena. The new methodology is based on a recently proposed elastoplastic bounding surface model, which has been implemented to the 2D finite difference code FLAC, via its User-Defined-Model capability. In particular, the emphasis in this paper is on comparing measurements to numerical results for the seismic response of a liquefiable sand layer that has a mild slope leading to the detrimental phenomenon of lateral spreading. The new methodology is proved capable of accurately predicting the time-histories of ground acceleration, excess pore pressure buildup and accumulation of displacements at all depths within the mildly-sloping liquefiable layer. Moreover, the new methodology provides insight to the mechanism of accumulation of displacement during lateral spreading.