Abstract:

In the rock slope stability analysis methods, the strength reduction method based on nonlinear Hoek-Brown criterion has some problems, such as the disunity of reduction schemes or the complexity of calculation. To solve this problem, a generalized Hoek-Brown criterion strength reduction method based on the compressive strength of rock mass is developed, which can better reflect the physical significance of strength attenuation than the direct reduction of material parameters. Based on the uniaxial compressive strength of rock mass, the uniaxial compressive strength of intact rock s_ci and the parameters’ combination s^a (s and a are empirical parameters of rock mass) are reduced by the same ratio, the reduction ratios of shear strength and the tensile strength are analyzed, and the factor of safety is defined based on the average shear strength. The proposed method is applied to the stability analysis of two classical slope examples, and the factor of safety and critical sliding surface obtained are compared with the local linearized strength reduction method and the limit equilibrium method. The results show that the factor of safety obtained by the proposed method is close to that obtained by the other two methods for two examples, and the relative error is less than 2%. In example 1, the location of the critical sliding surface obtained by the proposed method is in good agreement with the results of the other two methods. In example 2, the critical sliding surface of the proposed method is closer to that of the local linearization method, and can reflect both shear and tensile failures. The above results verify the reliability and rationality of the proposed strength reduction scheme and the definition method for factor of safety.

Key words: strength reduction method, slope stability analysis, generalized Hoek-Brown criterion, factor of safety, critical sliding surface