Shear performance of geosynthetic-encased stone column based on 3D-DEM simulation

Abstract

The shear performance of the geosynthetic-encased stone column (GESC) is of significance to the stability analysis of increasingly used GESC improved foundations, since the toe of the embankment is generally affected by lateral loads. However, systematic studies in this field are still scarce now. In this paper, a three-dimensional discrete element method (3D-DEM) was employed to study the shear performance of the unit cell with a single GESC and the surrounding soil. The influences of some physical geosynthetic parameters (e.g., geogrid strength, encasement aperture and column diameter) on the shear performance were examined. Higher shear strength of GESC was observed when increasing the geogrid strength. The reinforcement effect of geosynthetic encasement increased with the column diameter non-linearly, however, the encasement aperture was found insignificant. The failure features of GESCs were considerably affected by the geogrid strength and can be generally divided into three categories (e.g., bulging failure, shear failure and flexural failure). Moreover, the shear load transfer mechanism and the development of the shear stress ratio were analyzed. Correlations between the shear strength parameter of GESC (e. g., apparent cohesion) and geogrid strength were quantified for practical use.