The shear strength reduction FEM has been combined with the large finite element software ABAQUS

which has the strong functions to handle the calculated results.By dynamic manifestation of the development of generalized plastic strain in ABAQUS software

the generalized plastic strain and its development zone can be put as the evaluation criteria for the slope stability.By adjusting the size of the shear strength reduction factor F continuously

changing the magnitude of shear strength parameters c?φ of soils

the various development of the generalized plastic strain of slope under different reduction factors can be gained.When the plastic strain zone appears to run-through the top of slope

at the same time the plastic strain and displacement increase rapidly

it indicates that the slope has been at the critical state of breakage.Then this reduction coefficient can be defined as the minimum safety factor of slope.Through numerical analysis of a natural vertical slope and some excavated slopes

it is indicated that the proposed method in this paper can rather exactly predict the corresponding shape and position of the potential slip surface and the safety factor

and is especially simple to be applied to complicated cases.