Bearing Capacity of Annulus Stone Column Double-Encapsulated with Geotextiles

The behavior of annulus stone columns in soft clays is significantly influenced by the outer-to-inner diameter ratio. For this reason, in the present study, a comprehensive experimental investigation program was undertaken in the laboratory on a soft clay from Warangal, India, by varying its water content for achieving different undrained shear strength values and to determine the load-carrying capacity of conventional and annulus stone columns with different outer-to-inner diameter ratios that were double-encapsulated with geotextile. Investigations were also extended to determine the optimum L/D ratio and spacing between the groups of annulus stone columns. Based on these studies, a theoretical framework is developed for interpreting and determining the load-carrying capacity of the stone columns. The studies presented in this paper offer a novel ground improvement technique to enhance the load-carrying capacity of soft soils.