关键词: 边坡稳定性, 强度折减法, 双强度折减法, 折减配套机制, 折减路径函数, 临界状态

Abstract: Double reduction method (DRM) adopts reduction strategy which utilizes the different reduction coefficients of strength on the cohesion and internal friction angle and this view is more rational. However, the research on double reduction method still lacks of quantitative analysis or reasonable explanation. In the coordinate system of strength parameters, definition of FOS, path of reduction, and critical state are used to analyze the difference between traditional strength reduction method (SRM) and DRM. There is unity in path of reduction with these two methods; DRM can be regarded as the SRM where it begins at an initial virtual strength point to reduce. The gradual process of slope destruction is the attenuation of strength parameters. In this process, c and tan φ follow direct proportion function. At the same time, in the coordinate system of strength parameters, the concept of strength reserve can be reflected as the gradual process which is initial strength area approaches to critical strength area. Using these concepts can get the expression of the final FOS. Research of strength reduction method should concentrate on strength, and the reduction of strength parameters are just a way to achieve purpose of strength attenuation. Definition of FOS and regression analysis all indicate that critical state is inherent property of slope, given geometric model of slope, the critical state is constant, which is not related to initial strength parameters. The different critical points lead to the different results between DRM and SRM.

Key words: slope stability, strength reduction method, double reduction method, mechanism of matching reduction, function of reduction path, critical state