Reliability Analysis And Numerical Simulation For Three-dimensional Stability Of Slope

It is an especially important topic of development for slope stability analysis method investigation in geotechnical engineering. Now there is a lot of analysis methods, but various analytical methods have their limitations. Completed each other and gived fully the advantages of each method, the two or more coupling methods are a kind of future development trend. In this paper, the strength reduction method, finite element method and the limit equilibrium method are discussed.The calculation model of three-dimensional slope is established on simplified slope geological conditions. Used modified Mohr-Coulomb mode and the interface element, the slope is simulated by the Fast Langrangian Analysis of Continua in three Dimension. Two cases in slope have been simulated: an initial static loading is applied in the numerical model to simulate the prevailing soil conditions at the site,and rain condition is simulated. On the basis of average mean point method for the plane, with difference forms in replace of partial derivative form, the reliability index of the simplified calculation formula is deduced and combined with examples searching the largest global slope failure probability.Then the safety factor of three-dimensional slope using numerical strength reduction solving principle can be calculated. The reliability of three-dimensional slope is analyzed through the relation of the safety factor of slope and the rosenblueth method.The results show that (1)The mutual check between strength reduction method and limit equilibrium factor of safety calculation results is not strictly. Combinated with the reliability, the range of application of different calculation methods and calculation of results should be considered;(2)In the progress of the filling slope produces consolidation sedimentation and the filling soil slope equality subsidence ,the second step in the slope get up to the maximum displacement ;(3) The deformation under the gravity action, during the process of this stress redistribution, some tension cracks are generated on the grade surface and top of slope, and provides conditions for rain infiltration. Rain becomes the main reason for the failure of filling slope. On the one hand rainfall increases the weight of filling slope, on the other hand water in-filtration along the cracks softens the interface between the filling and original slope surface,which results in the slippage and instability of filling high slope. (4)The most dangerous sliding surface and the biggest failure probability of sliding surface is not the same. The simplified formula is not only a reliable indicator of the slope failure probability can be calculated, but also pointed out that the corresponding sliding surface. (5) Cohesion and internal friction angle variability affect the safety factor and displacement ,but they have the more sensitivity for internal friction angle.The coupled method of the numerical simulation and the rosenblueth method calculated slope failure probability have come true through numerical simulation strength reduction.The comprehensive analysis of multi-indexes included in the safety factor, stress and strain, plastic zone, failure probability can assess the slope ,which provide the reference for the similar project.