Abstract: The stability analysis of embankments reinforced by a single pile carried out by the authors shows that the limit equilibrium method can not consider the failure mechanism of the single pile at different locations and thus will overestimate the embankment stability when the composite shear strength is used. 3D and 2D numerical analyses are performed to study the stability of embankment supported by group rigid piles. The relative soil-pile displacement, internal forces and failure modes of piles are analyzed. The analysis results show that for the piles at different locations related to the embankment, the failure patterns and contribution to the embankment stability are different. The bending failure is more possible to occur than the shear failure. The cut-off mechanism is suggested and introduced into numerical analysis to consider the possible bending failure of piles when the embankment is approaching failure. The allowable shear strength of the piles is suggested when the limit equilibrium method is employed to analyze the stability of rigid piles supported embankment.