Stability Analysis Of Slightly Weathered Rock Slope Based On Strength Reduction Method

There are many methods for the slope stability analysis, the limiting equilibrium method is mainly used traditionally, the strength reduction method which analyses slope stability with finite element or finite difference method is introduced these years. According to the strength reduction method with finite difference , the factor of safety and the most dangerous slip surface can be obtained directly, the stress field and the process of destabilization can be shown too.This paper takes the slightly weathered rock as subject investigated, and uses the strength reduction method with finite difference based on FLAC-3D software to analyse the stability of slightly weathered rock slope.This paper researches the engineering characteristic of the slightly weathered rock slope, analyses the existing criterions of destabilization and takes the convergence criterion. This paper makes a program based on FLAC-3D software to carry out the strength reduction method, and gets the factor of safety and the most dangerous slip surface according to it. This paper takes one homogeneous slope and one heterogeneous slope as examples to test the self-orgnizing strength reduction method which is mentioned above. Based on the homogeneous slope, it simply analyses the influence to the factor of safety of the mesh, internal friction angle, cohesive strength, Young's modulus and Poisson's ratio. Finally it analyses an instance of the slightly weathered rock slope by the self-orgnizing strength reduction method. The conclusions are as follows:(1) Because of bad physical mechanical property of rock mass, low strength, so many structural planes and minor faults which leads to weak strip after weathered, the homeostasis of the slightly weathered rock slope is serious. With the influence of external factors such as rainfall, engineering projects and unreasonable job practicees, it's very easy to be unstable.(2) The mesh should be ploted reasonably in the process of model building. When the mesh density is low, the factor of safety reduces greatly with the increase of mesh density, when the mesh density is high, the factor of safety changes little with the increase of mesh density. The precision of calculation will not be nice if the mesh density is too low, contrarily it will cost too much time to calculate if the mesh density is too high. So it's normally need to confirm the reasonable mesh density according to pilot calculation.(3) With the same computational condition, internal friction angle influences the calculation of factor of safety greately, cohesive strength takes second place, Young's modulus and Poisson's ratio influences the calculation of factor of safety hardly.(4) The self-orgnizing strength reduction method based on FLAC-3D software in this paper is applicable, it can get reasonable factor of safety and the most dangerous slip surface.