Mechanism of Stone Columns for Mitigation of Liquefaction

Abstract

Stone columns have been used as an effective technique for improving the engineering behavior of soft clayey grounds and loose silt deposits. The soil improvement via stone columns is achieved by accelerating the consolidation of weak soil due to shortened drainage paths, increasing the load-carrying capacity, and settlement reduction due to the inclusion of stronger granular material. In the present study, two-dimensional numerical analysis was used to assess the effectiveness of stone columns and their improvement mechanisms, in mitigating liquefaction. A case study from 29 March 1999 Chamoli Earthquake was used as a basis of the research with the finite element software package PLAXIS 2D CONNECT Edition V21.00. The main improvement mechanisms of stone columns – densification, drainage, and reinforcement and their individual effects on the improved ground have been investigated. Generally, it is found that considering the densification and drainage effects in the analysis improved the performance of the stone columns, while the reinforcement effect made only a small difference.