Numerical Study of Effect of Encasement on Stone Column Performance

Encasing a stone column with a high-strength geosynthetic provides the column material with significant lateral confinement, which prevents lateral displacement of the column into potentially soft surrounding soil and consequently increases the bearing capacity of the column. Although this technique has been successfully applied in practice, the load transfer mechanism of encased stone columns and their performance in comparison with conventional stone columns have not been studied in detail. This paper describes three-dimensional finite element analyses that were carried out to simulate the behavior of a single stone column with and without encasement in a very soft clay soil using the computer program ABAQUS. A comprehensive study was performed to better understand the mechanism of load transfer in conventional stone columns and geosynthetic encased stone columns. The performance of partially encased columns was then compared to that of fully encased columns and conventional stone columns.