Numerical investigation on the dynamic behavior of GESC improved ground in dry sand

This paper presents a numerical investigation of the dynamic behavior of geosynthetic encased stone column (GESC) improved ground in dry sand. A pressure-dependent multi-yield model was adopted for soils, and the geosynthetic encasement was incorporated using linearly elastic geogrid elements. A three-dimensional numerical model was developed and validated against previously conducted shaking table tests, including comparisons of settlement, acceleration amplification factors, and encasement tensile strains. The validated model was then used to compare the dynamic responses of edge and central columns, followed by a parametric study assessing the influence of key design parameters on the dynamic behavior of edge columns. Results indicate that edge columns play a critical role in controlling lateral deformation by providing substantial shear restraint, thereby significantly reducing lateral displacement within the GESC improved ground. The geosynthetic encasement of edge columns is more susceptible to tensile rupture and experiences higher shear stress and strain compared with that of central columns, indicating a greater shear demand under dynamic loading. Increasing the encasement stiffness and the area replacement ratio enhances the foundation’s resistance to shear deformation and improves overall dynamic performance. These findings provide insights for optimizing the design of GESC improved ground subjected to dynamic loading.