Soil-rock mixture is different from conventional soil and rock materials. Inhomogeneity is an obvious feature of soil-rock mixture and the material component is one of intrinsic factors to influence the stability of soil-rock mixture slope. Mathematical intervals are defined for sort judgment basing on material component of soil-rock mixture. For each unit, sort judgment is dealt with by Monte Carlo method, and the corresponding value of the physico-mechanical parameter is given to unit of sort units. By this means, material component proportions of numerical model are equal to that of real states of soil-rock mixture slope. Stability analysis of soil-rock mixture slope is taken by the strength reduction method and the influence of material components contents on stability of soil-rock mixture slope is researched by numerical experimentations. The results indicate that it is unsafety to calculate the factor of safety by use of homogeneous slope model.
Strength reduction method of finite element is used to analyze the stability of slopes. The shear strength parameters are reduced until the slope to reach the ultimate failure state. So the factor of safety and the location of slip surface will be got directly by use of this method.
The strength reduction method is more rigorous than limit equilibrium method in theory, which meets equations of equilibrium, equations of strain compatibility and stress-strain relations of geomaterials, so the strength reduction method is widely used in the analysis of the stability of slopes. Many scholars had do a lot of researches for strength reduction method since this method is first proposed by Zienkiewicz in 1975, and with the development of compute technology, the strength reduction method is becoming a new trend in the area of slope stability analysis. When compared to the traditional limit equilibrium method, the strength reduction method can calculate safety factor without making any assumptions for shape and position of the sliding surface, and all information of stress, strain and displacement can be got. In addition, the slope with complex physiognomy and geological can be simulated by numerical simulation method that is not restricted by geometry, boundary conditions and material inhomogeneity of slope.
At present, the slopes often are considered as uniform slopes or layered slopes when the stability of slopes is analyzed by strength reduction method. But inhomogeneity is the basic characteristics for geotechnical materials.