Numerical analysis of soil liquefaction induced failure of embankments

Abstract

Soil structures such as river dikes, highway embankments, and earth dams have been frequently damaged during past major earthquakes. In most cases, large deformations occurred due to liquefaction of the supporting loose cohesionless foundation soil, resulting in cracks, settlement, lateral spreading, and slumping. Some researchers showed that river levees resting on non-liquefiable foundation soil have been damaged. In this regard, the base of such levees subsided in a bowl shape due to foundation consolidation that was shown to have the principal contribution to liquefaction as an underlying mechanism. This paper aims at describing the global dynamic response of a thin Loose Sand layer located buried in deep (10m) stratum of Clay (less permeable), situated at the foundation of a levee, due to liquefaction phenomenon. This study purpose is to reproduce such behavior by applying numerical simulations, adopting the open-source computational platform OpenSees. In particular, this study considers a 2D soil model of a levee subjected to earthquakes in order to investigate the failure of embankments induced by non-liquefiable soil foundation with a thin sand layer with partially drained condition. A parametric analysis using ground motions at multiple levels of intensity was performed to highlight the influence of parameters such as, the thickness of saturated zone, the permeability ratio between saturated zone and non-liquefiable soil (i.e. drain condition) on the obtained crest settlement and on the induced damage level of the embankment.