Simplified stability analysis method for GESC-supported embankments on soft ground

The confining effect of geosynthetics renders stability analysis of embankments on geosynthetic-encased stone columns (GESCs) distinct from conventional columns. A simplified method addressing this issue is practically important. This study proposes such a method for evaluating both seismic and static stability of GESC-supported embankments, modeling the confining effect as a combination of shear resistance along the slip surface and additional axial bearing capacity from vertical and circumferential tensile strengths of the encasement. The approach integrates pseudo-static analysis with limit equilibrium under a circular slip surface, explicitly considering the geosynthetic's stabilizing contribution and the varying shear resistance among columns intersected by the failure surface. Numerical validation with FLAC3D shows excellent agreement, with discrepancies of the factor of safety about 10%. Key findings include: (a) the equivalent shear strength provided by the encasement decreases nonlinearly toward the embankment centerline; (b) allowable geosynthetic strain negligibly affects slip surface geometry but has a nearly linear positive correlation with the factor of safety; (c) under moderate seismic loading, GESCs significantly outperform conventional columns, with progressive failure initiating at the embankment toe. The method reveals sequential column failure from toe to centerline and offers practical advantages for preliminary design and stability assessment in seismically active regions.