Study on the nonlinear behavior of soil–pile interaction in liquefiable soil using 3D numerical method

Abstract

An interface contact model was proposed to study the nonlinear behavior of soil–pile interactions during soil liquefaction in earthquakes. The soil–pile interface was modeled using joint elements that exhibit linear deformation in the elastic stage and slippage in the plastic stage. The joint elements can potentially model the separation between the soil and the pile. Based on the effective stress theory, an advanced fully coupled 3-D soil–water dynamic finite element–finite difference analysis was performed with different ground motions. In the analysis, a cyclic mobility model properly described the structure, consolidation, and anisotropy characteristics of the soil; the pile was modeled using a hybrid element with a beam and a column to consider the volume effect of the pile. Parametric studies of the interface were conducted to quantify the factors influencing the pile response. The potential soil–pile separation was also discussed. The results indicate that the soil–pile interface has a greater influence on the pile response in strong ground motion; consideration of pile volume is necessary for both small and strong ground motions. The potential soil–pile separation is indispensable in clarifying the soil–pile interaction mechanism and quantitatively estimating the pile response in earthquakes.