Slope Stability Analysis By The Manifold Element Method

Slope failure is one of the most popular disasters of geotechnical engineering. It is important to get a rational safety factor of slope.Now, there are three main methods, namely limit equilibrium method, plasticity limit analysis and FEM. Every thing has its two sides, analyzing a real slope needs application of several methods. Comparing with other methods, the FEM considers the slope constitutive model and can give the stress distribution. More and more people like to analyse slope stability with FEM.In this paper, a new method, numerical manifold method, is introduced, and applications of adaptive FEM, incremental elastoplastic theory and shear strength reduction technique are on second thoughts.Based on the numerical manifold method and limited covering, a 3-4 node plane triangle manifold element for consolidation analysis is put forward. By choosing the nodal covering function order of deformation and pore pressure independently, the interpolation of deformation and pore pressure in element can then be determined freely. No mesh refinement is needed to increase numerical precision. The numerical results show that the manifold element ( T1-0, that is to say the nodal covering function order of deformation and pore pressure are 1 and 0 respectively) can greatly improve the accuracy of Biot consolidation analysis, especially the initial pore pressure. And compared with the quadrangular isoparametric element, the manifold element ( T1-0 ) can give more accurate initial pore pressure and displacement and have a vast prospect of application.The adaptive finite element method is a numerical scheme which can automatically adjust algorithms to improve the solving procedure. Based on the manifold element method, Zienkienwicz and Zhu's error estimation is adopted. A fine mesh is got by automatic mesh generation.Soil body is nonlinear, and incremental elastoplastic can simulate it well. At the same time, several yield criterions are studied in order to find the best one. On thebase of above, a rational safety factor of slope is calculated with shear strength reduction technique.In the end, the case of mountain Lailong is analysed with the method of this paper. The results show the applicability of the method.