Stone columns, often referred to as granular columns or piles, are widely used to improve the ultimate load capacity (ULC) of untreated soil and to reduce ground settlement. In soft soils, excessive settlement can occur under vertical loading due to insufficient lateral support from the native soil. This challenge is effectively mitigated by encasing stone columns in geosynthetic materials that possess high axial stiffness, providing additional confinement. This paper examines the performance of vertically encased geosynthetic stone columns (GESCs) through finite element analysis using Plaxis 3D, simulating the unit cell concept. A series of numerical models were created to assess the load-settlement behavior of GESCs under short-term loading conditions. The study focused on various parameters, including column diameter, length, internal friction angle of the column material, encasement length, and geosynthetic stiffness. The results indicate a significant enhancement in the ULC of the columns when encased in geosynthetics, with the ULC of GESCs increasing by four to eight times compared to untreated clay beds. Additionally, the ultimate load capacity of the GESCs-treated ground increases with higher area replacement ratios. These findings underscore the improved load-bearing capacity of geosynthetic-encased stone columns, confirming their effectiveness as a ground improvement solution.