Seismic evaluation of embankment-type structures with coupled hydro-mechanical model
Résumé
The response of geotechnical structures under earthquake loading is highly nonlinear and often leads to problems of slope stability, foundation settlement and soil liquefaction. The prediction of these failure modes is a topic of great interest in geotechnical earthquake engineering, particularly for structural integrity assessment, which requires estimation of structural behavior during and after collapse. In this study, the earthquake response of a road embankment resting on a soil foundation is investigated. Both fully drained and coupled effective stress analysis are performed. Moreover, two different soil types are used for the embankment (loose-to-medium and medium-to-dense sand). In the fully drained case, no failure of the embankment is observed for the medium-to-dense sand and for a certain level of ground motion. However, in the coupled effective stress simulation, for the same material and input motion, liquefaction of the foundation soil can lead to the generation of a thick shear band which produce large settlements and accelerate the failure of the embankment. The response of the loose-to-medium sand is fundamentally different, as several localization zones are generated, at the foundation part and inside the embankment body, as well. In both simulations - fully drained and coupled effective stress analyis - the embankment fail can occur due to shear band generation inside the embankment.