Numerical Investigation of Liquefaction Behavior and Lateral Spreading in Poorly Graded Fine Sand Reinforced By Stone Columns-Paper

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The study evaluates stone columns (SCs) as a method for reducing earthquake-induced liquefaction and lateral spreading in the poorly graded fine sands of Bhopatpur, Bahraich, India. The site has a shallow water table (0.5 m), loose-to-medium-dense sand, and high liquefaction susceptibility: preliminary analysis indicates severe susceptibility to a depth of 7.5 m, with a Liquefaction Potential Index of 13.13.<br /><br />Three-dimensional, fully coupled finite-element simulations were conducted using OpenSeesPL and a pressure-dependent multi-yield soil model. The model was checked against VELACS centrifuge test data, then used to compare untreated and stone-column-improved ground under earthquake loading. The researchers examined the effects of column area replacement ratio, diameter, and permeability on lateral spreading and excess pore pressure (EPP).<br /><br />In the benchmark case, stone columns with a 0.6 m diameter and 20% area replacement ratio reduced maximum lateral spreading from 3.57 m to 0.594 m—about 83%. They also limited EPP generation, particularly near the columns, and reduced shear strain in the surrounding soil. Increasing the area replacement ratio or column diameter generally further reduced lateral deformation. Higher column permeability had a particularly strong effect: increasing permeability from 0.01 to 1.0 m/s raised the reported reduction in lateral spreading from about 83% to 94%, while substantially lowering EPP at the model center.<br /><br />Overall, the numerical results indicate that stone columns can improve drainage and ground stiffness, thereby mitigating liquefaction-related deformation in loose, saturated fine sand. The findings suggest that column spacing, diameter, and permeability are important design considerations for seismic ground improvement.

Keywords

stone columns

liquefaction mitigation

lateral spreading

earthquake loading

excess pore pressure

finite element simulation

OpenSeesPL

ground improvement

seismic soil response

permeability effects