A DEM Study on Bearing Behavior of Floating Geosynthetic-Encased Stone Column in Deep Soft Clays

The use of geosynthetic-encased stone columns has been proven to be an economical and effective method for soft soil foundation treatment. This method is widely used in civil engineering projects at home and abroad. When the geosynthetic-encased stone columns are applied to deep soft clays, they are in a floating state. The load-bearing deformation mechanism of geosynthetic-encased stone columns has changed. The interaction between the aggregates, geogrid, and soil is worth studying, especially at the bottom of the column. In this paper, the discrete element method is used to simulate a floating geosynthetic-encased stone column with a 280 mm encasement depth in deep soft clays. The load-bearing deformation characteristics and mesoscopic mechanism of the floating geosynthetic-encased stone column are studied. The results show that there are large vertical and radial stresses in the top region. Moreover, the porosity and sliding fraction of aggregates in this region increase with settlement, and the coordination number decreases with settlement. The vertical and radial stresses of the soil near the column body are not affected much by the column body. When the encasement depth exceeds 280 mm, the bearing capacity of the FGESC does not increase much. The encasement depth controls the failure mode of the floating geosynthetic-encased stone column. As the encasement depth increases, the failure mode of the floating geosynthetic-encased stone column gradually transitions from swelling deformation to penetration failure.