Static and cyclic responses of end-bearing and floating geosynthetics-encased steel slag columns via model tests

Geosynthetic-encased stone column (GESC) has been widely adopted as a reinforcing technology for various civil projects in soft soils due to its enhancement of load-bearing capacity and drainage efficiency. Despite existing substantial body of research, the performance of GESC under cyclic loading and the potential benefits of using steel slag as an alternative aggregate remain underexplored. This study presents a comprehensive experimental investigation comparing the performance of end-bearing and floating geosynthetic-encased steel slag column (GESSC) under static and cyclic loading through model tests. Key parameters including settlement behavior, stress transfer efficiency, pore water pressure distribution, moisture migration, and undrained shear strength were systematically analyzed. The results demonstrate that end-bearing GESSC significantly outperforms floating column in terms of settlement control, load transfer to the bearing stratum, and pore pressure dissipation, especially under repeated cyclic loading. In contrast, floating columns more effectively mobilize shaft friction and enhance shear strength in the upper soil layers. These findings contribute to a better understanding of load transfer mechanisms in GESSC and provide practical guidance for their application in infrastructure projects subjected to dynamic loading conditions, while also promoting the reuse of steel slag as an environmentally beneficial fill material.