Abstract
<title>Abstract</title> <p>This study numerically investigates the performance of geosynthetic-encased stone columns (GESCs) on soft clay exhibiting low bearing capacity and excessive settlement. Numerical models were developed to evaluate the influence of key parameters; geosynthetic stiffness, encasement length, and column arrangement on the load-bearing behaviour, settlement response, and pore water pressure dissipation of GESCs, both individually and in group configurations. The results demonstrate that increasing geosynthetic stiffness to 1500 kN/m yields a 264% improvement in ultimate bearing capacity (UBC) relative to untreated soft clay, while settlement reductions of nearly 30% were observed across various configurations. Full-length encasement (100%) was found optimal, increasing UBC by 164%, highlighting the critical role of encasement length in controlling radial bulging. GESCs also showed markedly lower early-phase and long-term settlements compared to ordinary stone columns (OSCs) and untreated clay, with long-term settlement progression remaining below 1 mm over 100 days up to 566% lower than unreinforced clay. Furthermore, GESCs exhibited faster and more effective pore water pressure dissipation, reducing the risk of hydraulic instability. Group analysis revealed that GESCs installed collectively outperform single-column systems. Overall, the findings confirm that GESCs significantly enhance both short- and long-term foundation performance, offering an effective and reliable ground improvement solution for embankments constructed on soft clay, while emphasizing that both quantitative and qualitative design factors must be considered for optimal implementation.</p>