Abstarct: Abstract Stone columns are used as an option to improve the bearing capacity of weak soils and to reduce settlement in structures built on such soils. The use of geosynthetics, which are known as soil reinforcements, can effectively improve the bearing capacity and reduce settlement. Although this ground improvement method is now widely used, few studies have been conducted in this field. In this research, preliminary tests were performed to identify the materials and particle size distribution of the stone column. Furthermore, by modeling a stone column without considering the surrounding soft soil, the bearing capacity of a single stone column was investigated using a triaxial apparatus on a sample with a height of 20 cm and a diameter of 10 cm (height-to-diameter ratio of 2) under consolidated drained (CD) conditions. The CD method was selected because of the drainage capability of the stone column. Geosynthetic reinforcements with both drainage capacity and good tensile strength, such as geotextiles, were used to improve the bearing capacity and reduce settlement. In this study, one type of woven geotextile with a weight of 100 g/m² and three types of nonwoven geotextiles with weights of 200 g/m², 300 g/m², and 400 g/m² were used. The geotextiles, acting as reinforcements, were wrapped vertically around the column with a 2 cm overlap length and confined through interlocking between aggregates. The samples were tested under confining pressures of 75 and 150 kPa, using two soil gradations: Soil 1 (4.75–9.5 mm) and Soil 2 (9.5–12.5 mm). The results indicate an improvement in the bearing capacity of the stone column for both soil gradations with all types of reinforcements. The maximum percentage increase in bearing capacity compared to the unreinforced sample for Soil 1 at a confining pressure of 75 kPa was 230%, and for Soil 2 it was 200%. At a confining pressure of 150 kPa, the increases were 152% for Soil 1 and 182% for Soil 2. The woven geotextile with a weight of 100 g/m² showed the best performance due to its woven structure, especially at 75 kPa confining pressure in Soil 1, with an increase in bearing capacity up to 2.3 times, a reduction in volumetric strain up to 3 times, a decrease in radial strain by 26%, and an enhancement in reinforcement effect up to 2.3 times compared to the unreinforced sample. Moreover, the 100 g/m² woven geotextile was able to induce a confining pressure up to twice the applied cell pressure. However, for Soil 2, this woven geotextile exhibited the highest bearing capacity at 150 kPa confining pressure, reaching 1.82 times that of the unreinforced sample, with a reduction in volumetric strain up to 6 times, a decrease in radial strain by 44%, and an increase in reinforcement effect up to 1.82 times compared to the unreinforced sample. In this case, the induced confining pressure was approximately equal to the applied cell pressure. Therefore, it can be concluded that at higher confining pressures, using coarser aggregates improves the bearing capacity, while at lower confining pressures, finer aggregates lead to higher bearing capacity. Additionally, it was observed that for all samples, the maximum bulging due to loading occurred between 0.5D and D from the top of the column, and when the geotextile was woven, the lateral deformation (radial strain) reached its minimum value. Furthermore, among the nonwoven geotextiles, the 300 g/m² sample exhibited behavior similar to that of the woven geotextile, due to the effective contact surface between the geotextile and coarse particles and the improved mobilized friction angle, despite the lower tensile strength of the 300 g/m² nonwoven geotextile compared to the woven one.