Using Stone Columns to Mitigate Lateral Deformation in Uniform and Stratified Liquefiable Soil Strata

Abstract

On the basis of a systematic parametric study, three-dimensional (3D) finite-element (FE) simulations were conducted to evaluate mitigation by the stone column (SC) approach. Mildly sloping saturated cohesionless strata (uniform as well as stratified) were investigated under the action of an applied earthquake excitation. For that purpose, the open-source computational platform OpenSees was employed, through a robust user interface that simplifies the effort-intensive pre- and postprocessing phases. Specifically, a number of SC configurations (1 × 1, 2 × 2, and 4 × 4) for a given area replacement ratio (Arr) were explored. In these configurations, the same Arr was maintained by deploying smaller-diameter columns, evenly distributed spatially so as to increasingly reduce the drainage path. As such, it was found that a more evenly distributed SC configuration (e.g., the 2 × 2 configuration compared to the 1 × 1), with a shorter drainage path, is more effective in decreasing the soil lateral displacement. Site stratification was found to have a potentially highly significant influence on the accumulated lateral ground displacement. The involved localized deformation mechanism may have an important influence on the SC response and efficacy. Overall, the conducted study provides insights for defining an economical and effective remediation solution.