This study presents a numerical investigation of the performance of sand columns installed in clayey soils. The columns are installed using the replacement method, following several techniques. After validating the numerical model, a parametric analysis was conducted to assess the influence of key parameters, such as the area replacement ratio, column length, geogrid encasement, and the effect of the applied compaction pressure during column installation. The simulation results reveal that the effectiveness of the reinforcement increases with higher area replacement ratios, longer column lengths, and the presence of geogrid confinement. Furthermore, compaction during installation significantly improves the stiffness of the surrounding soil matrix, leading to a marked reduction in surface settlement. These findings highlight the crucial role of installation methodology in the overall performance of ground improvement systems.