This paper investigates the response of reinforced granular columns. Reinforcement is provided by applying horizontally laminated reinforcing sheets to the granular columns. An analytical procedure based on the normalized relation between the volumetric and axial soil strains is proposed to analyze column expansion. The proposed analytical method is verified through laboratory triaxial tests carried out on sand columns reinforced with four layers of horizontal geotextile sheets. Parametric studies over the reinforcement stiffness, reinforcement strength, granular column radius and spacing of the reinforcing sheets are conducted to investigate the effect of horizontal reinforcement on the column. Analytical results reveal that the interactive mechanism at the soil–inclusion interface and the mechanical behavior of the inclusion significantly affect the axial stress–strain response of the reinforced column. Because columns embedded in clay are subjected to continuously increasing confining pressure from the surrounding clay as a counteraction to column expansion, the analyses show that the reinforced granular column embedded in clay exhibits a significant increase in axial resistance over columns loaded under constant chamber pressure.