Improvement And Application Of Slope Three-dimensional Limit Equilibrium Method

Landslide disasters happen in China frequently. Landslide brings about seriouslosses to building facilities, water conservancy project, railway engineering and road,etc. Two-dimensional limit equilibrium method, which based on Mohr-Coulomb yieldcriterion and static equilibrium, is the most commonly used method in analysis ofslope stability at home and abroad. Assume that the slope is in a plane strain state,two-dimensional limit equilibrium method uses a limited amount of two-dimensionalprofile to replace the real three-dimensional sliding mass for stability analysis.Because two-dimensional limit equilibrium method ignores the horizontal boundaries,the calculations are so conservative. Three-dimensional limit equilibrium method canconsider the friction resistance of the slip surface flank, so the results reflect thepractical situation of sliding mass. Based on the existing study of three-dimensionallimit equilibrium method, this thesis put forward a new improvement method andapplied to two engineering projects. The main aspects of research and conclusions inthis thesis are as follows:1. Meanwhile consider the impact on slope stability by the inter-atomic forces andthe orientation of bottom sliding surface shear force. Assume that the included angleof the shear force of bottom sliding surface and main sliding direction can beexpressed by using assumed distribution function. Different distribution functions canreflect the asymmetry of the sliding surface. Assumed that the column interface is inthe limit equilibrium state, the calculation formula of slope safety factor can bededuced based on three-dimensional static equilibrium conditions of each column.2. Based on the basic theory of the improvement three-dimensional limitequilibrium method, use VC++language to self work out the visualization applicationprogram, and realize to calculate three-dimensional limit equilibrium method of slope stability. The program can calculate easily the slope safety factor and the sliding forceand resistance of the strips, and realize the program calculation of improvementthree-dimensional limit equilibrium method, Janbu method and Sarma method.3. According to the engineering projects of Jiuzi collapse deposit and Mao-pinglandslide, engineering stability were analyzed with improvement three-dimensionallimit equilibrium method. The result of calculation was contrasted withtwo-dimensional limit equilibrium method, two-dimensional finite element methodand three-dimensional finite difference method, the compare results showed that themethod in this paper was feasible and practical. After contrasting of two-dimensionaland three-dimensional calculation result, the impact of slope stability calculated bytwo different methods was discussed. Slope slide force and sliding resistance werestudied in this thesis, the result provided the basis of protection and managementmeasures.4. Apply the improvement three-dimensional limit equilibrium method, Janbumethod and Sarma method to calculate the horizontal sliding force and slidingresistance of the slope different profiles, and provide the basis for protective measures.The calculation results showed that the horizontal sliding force and sliding resistanceof the cross section appeared the distribution law of being small on both sides and bigin the middle.