Abstract: The stability analysis of geosynthetic-encased stone column (GESC) composite foundations is a critical aspect of design calculations, but research in this area is still incomplete. This paper categorizes GESCs under embankments based on their distinct failure characteristics. Considering the compression and bending failures of columns, the stability analysis method for GESC composite foundations under embankments is studied. Initially, this paper proposes a method to calculate the theoretical critical bending moment of GESCs, considering their physical properties and using the quadratic approximation method for solving transcendental equations, by referring to the calculation method for the bending bearing capacity of reinforced concrete piles. Subsequently, the concepts of critical bending moment and equivalent shear strength are introduced to modify the traditional limit equilibrium method, and a stability analysis method based on bending failure of columns for GESC composite foundations under embankments is proposed. Finally, the results of the method, the traditional limit equilibrium method, and the numerical strength reduction method are compared using an example of laboratory model test, to verify the rationality and applicability of the method.

Key words: embankment, geosynthetic-encased stone column, composite foundation, stability analysis, bending failure