Geotextile thickness effect on slope failure stress of encased column: 3D numerical study

The stability of uncertain earth slopes continues to pose a substantial challenge in geotechnical engineering, with an increasing necessity for effective reinforcement against various loadings. This investigation presents a 3D numerical analysis exploring the functionality of geotextile-encased stone columns (GESC) in sand slope stabilization. The research demonstrates that a GESC, optimally situated in the central region of the sand slope, enhances stability to an ideal level. Additionally, an upper threshold in geotextile thickness is identified, beyond which further increments fail to augment the slope's bearing capacity. A 20 mm geotextile thickness is found to yield maximum bearing capacity, with an optimal center-to-center distance to the diameter of stone columns (S/D) ratio of 2. The study also posits the feasibility of increasing the S/D ratio to 2.5 at optimal geotextile thickness while underscoring that a reduced S/D does not inevitably denote an increased bearing capacity. Interestingly, while encasement of the central stone column does not substantially amplify bearing capacity, the encasement of lateral columns significantly bolsters it, augmenting bearing capacity by 40% and reducing vertical displacement by 14%. The numerical findings align well with corresponding experimental results, thus corroborating the efficacy of GESC in sand slope stabilization.