3D Numerical Investigation of Slope Stability using Geogrid Reinforced Stone Column

One of the efficient ways in order to reinforce the earth slopes is Geogrid Encased Stone Column (GESC). This technique can increase bearing capacity and decrease settlement rate of slopes. The aim of this study is to perform a three dimensional finite difference method (FLAC3D) for GESC in the stabilization of sand slopes. According to the results of 3D numerical analysis, the existence of geogrid-encased stone column, increases stability to an ideal level compared with ordinary stone column-reinforced slopes. Different parameters including stone column diameter, the coupling spring stiffness, coupling spring cohesion, coupling spring friction, S/D ratio, and the layout of encasements evaluated and discussed in this paper. The influential parameter in geogrid in order to reinforce stone column, is coupling spring cohesion. By increasing the parameter, slope bearing capacity of reinforced slope increases linearly. This indicate that use of geogrid reinforced stone column, based on type of geogrid characteristics, can enhance earth slope bearing capacity up to 1.8 times of slope reinforced by ordinary stone column. The maximum bearing capacity with a row of stone columns was obtained for S/D=2. However, the reduction of S/D does not necessarily imply the increase of bearing capacity of slopes.