Based On Nonlinear Finite Element Method Of Rock Excavation Stability Analysis Method

Currently, there are many kinds of the theories and methods of the slope stability analysis, the common calculation methods are the limit equilibrium theory, the finite element method, the reliability analysis and the fuzzy theory. With the development of computer technology, solid mechanics and the nonlinear theory, the finite element method is wide applications to the analysis of the slope stability. The finite element method not only can carry on an appraisal quantitative of slope stability, but also can consider the discontinuity in rock, the relationship of the non-linear characteristics of stress and displacement, and mechanical anisotropy of rock. FEM can calculate elastic distortion and destruction state of rock. It can also take account into stress or constructing stress between structure surfaces, as well as some function and influence of specified conditions.This paper briefly reviews and comments the analytical methods of the rock slope stability. The basic principles of the nonlinear FEM for the stability of the rock slopes are systematically investigated, and the nonlinear FEM appled to analyse of the rock slope stability of the left bank of a right flushing & flood relief low-level outlet for a large-scale hydro power project. Local area on the left side of the right flushing & flood relief low-level outlet was cut by structure surfaces, the rock is a poor integrity and the rock mechanics parameters are low. The slope stability before and after excavation directly relate to the works' safety, the construction progress and the budget. In view of this, it is necessary to undertake a comprehensive evaluation of the slope stability.The normal and tangential stresses of a sliding surface can be directly obtained from FEM results, which can avoid the artificial assumptions and overcome most shortcomings of the limit equilibrium analysis methods. The results of the study show that the method based on FEM can accurately assess and predict the rock block stability and possible sliding trends.