Finite Element Strength Reduction Issues Related To Research And Engineering Applications

Compared with the traditional limit equilibrium method,the superiority of the finite element mehtod in slope stability analysis is obvious. The finite element method based on the strength reduction technique have been increasingly applied to the numerical analysis of slope stability .However, strength reduction FEM still got many issues on slope stability analysis.In this thesis, the key issues related to strength reduction FEM are discussed. The main work includes the following parts.(1)Based on summing up documents of slope stability analysis methods, research findings on strength reduction FEM have been summarized in particularly.(2) Types and advantages of nonlinear FEM as well as non-linear finite element program PLAXIS have been introduced. According to solution methods of nonlinear FEM equations such as iterative method, iterative method and hybrid method, their basic theory, solution procedure and rapidity of convergence and so on have been discussed.(3) Basic theory of strength reduction FEM has been introduced and the selection of its strength criterion,flow rule, the position of sliding surface of the slope as well as the influence of some factors (meshing density and boundary range etc.) have been discussed. Failure criteria of slope in strength reduction FEM has been particularly studied. Rational failure criteria of slope has been acquired by analysing several different kinds of slopes. Combined with the slopes of hanshi hignway, the rationality of the achievement have been tested and verified.(4) For convenient applications of strength reduction FEM in analysis of slope stability, the range of reduction coefficient of the strength reduction FEM has been studied. This article put forward a method that can attain convenient applications in slope stability analysis by making 1 as a starting point of reduction coefficient. Rationality of this method has been verified by analysing the factor of safety and sliding surface of the slopes of the Beijing-Zhuhai National Highway. (5) Longshan 110KV electric substation excavation slope stability has been analysed and the feasibility of treatment measures of the slope has been discussed.