Numerical Investigation of Key Parameters Influencing Stone Column Behavior and the Impact of Column Arrangement on Liquefaction Mitigation in Sandy Soils

Abstract

One of the most critical challenges faced by geotechnical engineers is soil liquefaction and its associated damage. When saturated soil is subjected to seismic vibrations, its static equilibrium is disrupted due to irregular dynamic forces, leading to the occurrence of liquefaction. This study first validates the numerical model using the results of VELACS physical modeling. Subsequently, a 3D numerical analysis is conducted using FLAC 3D to perform a parametric study on the factors influencing the pore water pressure generation, such as ground acceleration, soil compaction, and stone column dimensions. The results indicate that an increase in the stone column diameter consistently reduces settlement and horizontal displacement. However, this trend diminishes for diameters exceeding 0.8 m. With an increase in peak ground acceleration, soil mass displacement increases in all earthquake scenarios. A nearly linear relationship is observed between acceleration increase and excess pore water pressure at distances of 3.5 and 5 m. On the other hand, higher soil compaction reduces displacement but has a limited effect on decreasing excess pore water pressure within the soil mass. The findings reveal that the effective influence range of stone columns extends up to 1.5 m in all directions, beyond which the impact on liquefaction mitigation is minimal. Therefore, it is recommended to install stone columns at a maximum center-to-center spacing of 3 m. A configuration involving multiple stone columns demonstrated superior performance in dissipating pore water pressure and limiting deformations, especially at larger distances and depths. The results contribute to a more robust understanding of stone column behavior under dynamic loading and offer a practical framework for their effective implementation in earthquake-prone regions.