Abstract:Geo-encased stone columns are novel types of columns wrapped in layers of geosynthetics. They retain the excellent performance of stone columns and fully exploit the tensile properties of geosynthetics, which can improve the rigidity, shear resistance, and drainage effect of stone columns. However, few studies have focused on the liquefaction of sandy soil reinforced by geo-encased stone columns. In this work, shaking table tests on the liquefaction of sandy soil without reinforcement, reinforced with geosynthetic-encased stone columns, or reinforced with stone columns are carried out to investigate and compare the anti-liquefaction performances of the reinforcements. Results show that during vibration loading, the geo-encased stone columns consistently maintained their integrity and good drainage performance. Compared with those of the non-reinforced foundation and the foundation reinforced with stone columns, the total settlement values of the foundation reinforced with geosynthetic-encased stone columns decreased by 50% and 31.8%, respectively. Moreover, the amount of discharged water of the foundation reinforced with geosynthetic-encased stone columns increased by 33.3% and 16.6%, respectively, relative to those of the non-reinforced foundation and the foundation reinforced with stone columns. Excess pore water pressure in the foundation reinforced with geo-encased stone columns has drastically reduced, and sand liquefaction does not occur in lower portion of the foundation. The drainage performance of the foundation reinforced with geo-encased stone column tends to improve as the vertical depth of the soil increases. The seismic performance of geo-encased stone columns is better than that of stone columns.
