Abstract: Based on strength subtraction,through practical project cases,the slope failure process under the three kinds of elastoplastic models w analyzed numerically to explore the slope surface deformation law in this process. The results show that the safety factor is obtained by the reduction coefficient corresponding to the deformation mutation point,which provides ideas for the study of the relationship between deformation and slope safety factor.And that conducives to the establishment of slope monitoring and early warning system,and is of great significance to the progress of slope engineering informatizationin the future.

Key words: slope, elastic modulus, deformation, strength reduction