INNOVATIVE APPLICATION OF SINGLE AND DOUBLE COIR GEOTEXTILES FOR SUSTAINABLE STABILIZATION OF SOFT CLAY USING STONE COLUMNS UNDER ACT IS 15284-1:2003INKODUMUDIPANCHAYATH UNION, TAMILNADU, INDIA

Soft cohesive soils present serious challenges for infrastructure development due to their low bearing capacity and high compressibility. Stone columns (SCs) are widely used to improve soft soils; however, in very soft clays, insufficient lateral confinement leads to bulging and reduced performance. Synthetic geotextiles have been used as encasements to mitigate this, but their environmental impact has driven the need for biodegradable alternatives. This study explores the innovative application of Single Geopanama Coir (SPC), Double Geopanama Coir (DPC), and Jute geotextile as natural encasements for stone columns. Laboratory experiments were conducted in reconstituted soft clay beds (cu ≈ 33 kPa, w = 50%) replicating field conditions reported at the Kodumudi site, Erode District, Tamil Nadu, where silty clay and clayey soil strata with low SPT-N values (8–12) and safe bearing capacity of 60–70 kN/m² were identified. The performance of SCs encased with SPC, DPC, and jute was compared against unencased and synthetic encasement configurations across varying aspect ratios (L/D = 0.33–1.0). Results reveal that SPC-encased columns significantly enhance floating column performance, offering superior lateral support and load capacity, while DPC excels in end-bearing configurations, providing greater confinement and stiffness due to its dual-layer structure. The study identifies material-specific performance characteristics and highlights stitching limitations in natural geotextiles under large deformations. Overall, the research establishes natural coir geotextiles as viable, eco-friendly substitutes for synthetic encasements in soft clay stabilization, with direct applicability to sites like Kodumudi, thereby aligning geotechnical innovation with sustainability goals.