This study investigates the performance of vertical geotextile encased stone columns (VGESC) and horizontal geotextile coatings reinforced stone columns (HGCRSC) in a small-scale physical model under 1-g conditions. The study focuses on a sand slope in Kermanshah, Iran, presenting a novel exploration of employing VGESC and HGCRSC in sandy slopes. The research aims to provide valuable insights into the influence of geotextile layers in encasement and laminated coatings on the stability of supported sand slopes. The experimental setup involves saturating a sand slope model through artificial rainfall and reinforcing it by installing a vertical geotextile encasement around the stone column and incorporating horizontal layers of geotextile within the stone column. The precision of experimental findings is validated through 3D finite difference numerical analysis. Laboratory and numerical results indicate that geotextile-reinforced stone columns positioned in the middle of the sandy slope (considered an optimal zone for stability enhancement) significantly improve the resilience of the reinforced slope. Notably, VGESC exhibits slightly superior effects compared with HGCRSC. The results highlight a 62% increase in the bearing capacity of the studied sand slope using geotextile layers. Additionally, the reinforcing component alters the failure mode of stone columns from shear to bending failure, presenting a crucial aspect of this study.
