Abstract: There is an inherent relationship between deformation and strength parameters for a typical rock mass. From the perspective of material properties, the essence of the strength reduction method (SRM) is to search another appropriate rock mass, which could lead to a slope at the critical state under the current slope conditions. It is obvious that when the cohesion and friction angle are reduced but other mechanical parameters remain unchanged, the new mechanical parameters may be contrary to the inherent relationship, and thus the newly found rock mass might not be exist objectively. Therefore, it is necessary to adjust the mechanical parameters of rock mass during the reduction of cohesion and internal friction angle. Based on the above analysis, we propose a strength reduction method which considers the deformation and strength parameters of the coordination fold reduction. Then, the deformation parameters (i.e., elastic modulus and Poisson's ratio), tensile strength of safety coefficient, plastic zone are discussed in detail. The results indicate that the safety factors obtained by the proposed method are very close to those calculated by the limit equilibrium method. In addition, the distribution of the plastic zones in the failure slope is in agreement with that of the real slope state. The plastic shear zones mainly appear near the free face of a slope, while the plastic tensile zones largely locate at the top of the slope.

Key words: strength reduction method, deformation parameters, tensile strength, safety factor, plastic zones