Response of embankment on liquefiable soil to sequential ground motions considering mitigation measures

Abstract

The present study focused on gravel berm and stone column improvement techniques for mitigating the effects of liquefaction for an embankment resting on liquefiable ground. Three-dimensional finite element models are developed to evaluate the effectiveness of two countermeasure techniques for embankments resting on liquefiable soil. Three different embankment models are considered in this study as benchmark embankment model (BM), gravel berm embankment model (GBM), and stone column mitigation model (SCM). Foundation soil has been modeled using an elasto-plastic effective stress-based UBC3D-PLM model. Initially, the behaviour of three different embankment models (BM, GBM, and SCM) are evaluated under varying amplitude of cyclic input motion. Later, a seismic study is carried out considering 10 sequential earthquake motions to assess the effect of the aftershock following the main shock event. It can be seen that even small amplitude aftershocks can develop a high excess pore pressure ratio in the foundation soil, especially below the embankment toe. Moreover, a linear correlation has been observed between the input motion Arias intensity and the intensity at the embankment crest. In an overall observation, stone column mitigation was found to be a sound mitigation approach.