DEM-FDM numerical investigation on load transfer mechanism of GESC-supported embankment

Abstract

This paper presents a numerical investigation on the load transfer mechanism of geosynthetic-encased stone column supported embankment. A coupled numerical model is developed by combining the discrete element method (DEM) with the finite difference method (FDM). A parametric study is then conducted on several governing factors such as the encasement length (Lenc), geosynthetic stiffness (J), the strength of foundation soil (cu), embankment height (Hemb), and area replacement ratio (αE). The predicted stress concentration ratio (SCR) under the embankment load is smaller than that under rigid loading (i.e., under the equal strain condition of the composite foundation). The predicted coefficient of the lateral pressure (Kps) lies between the coefficient of earth pressure at rest (K0) and the coefficient of passive earth pressure (Kp). Particularly, the bearing capacity of the GESC would be overestimated when substituting the confinement with Kp in the calculation. The shear stress at the column-soil interface (τcs) is less than the ultimate shear stress, and its development would be retarded with depth.