The Theory And Programming Implementation Of Limit Equilibrium Method Based On The Finite Element Stress Field

Natural slopes and artificial slopes (such as dams and subgrades) can be found everywhere.The failure of slope can be a serious hazard to both human’s life and property. Thus, the stability analysis of slope plays an indispensable role for both academic value and economic benefits.The analysis of slope stability is a classic problem of Geotechnical Engineering. Many methods have been used to study these problems.The two most widely used methods are Slice Method and the Shear Strength Reduction Method. However, the slice method depends on the assumption of forces between slices.Furthermore, under a complex geological condition, it may be difficult to find the critical sliding surface. While the Finite element Shear Strength Reduction Method is disputable because of the selection of constitutive model and the criterion of safety coefficient.This thesis proposes another possible method to evaluate the slope stability, limit equilibrium method based on the finite element stress field (LEM-FESF). In this study, firstly, the theory of LEM-FESF was established. According to the thoery, a program was developed using C#computing language.Then this method was utilized to analyze the stability of soil slope.The results from LEM-FESF were compared with the results from Slice Method and Shear Strength Reduction Method, leading to the following findings:1) The results of the Finite element Limit equilibrium Method in the analysis of slope stabily is approximately similar to the results of Slice Method and Finite element Shear Strength Reduction Method,thus it can be used as an effective supplement method of the analysis of slope stability.2) The Finite element Limit equilibrium Method is affected by the stress field which is acquired by finite element method. Generally, based on the elastic solution of stress field, the results of this method is more similar to the results of Slice Method, while based on the plastic solution of stress field, the results is more close to the results of Finite element Shear Strength Reduction Method.3) In this research, another attemption is the stability analysis of slope using large deformation FEM. For some certain slope engineering, when the deformation is too large, the simulation cannot be continuously carried out because of the mesh distortion and calculation convergence. However, with the aid of Afena software, which utilizesRemeshing and Interpolating Technique with Small Strain (RITSS) method,the sliding surface and scale of the instability of slope can be simulated directely and accurately.