Research On Mechanism Of Stablity And Deformation Of Rock Slope Failure

As an important form of landslide,toppling damage often occurs in layered rock slopes of water conservancy and hydropower project,railways project,highways project,mines project and so on in China.In this context,this paper studies the stability and deformation mechanism of the toppling damage of rock slope by means of limit equilibrium method and numerical simulation method.In terms of numerical simulation analysis,the block discrete element method which is more suitable for simulating the jointed rock system is selected,and UDEC software for simulation is used.The main work and achievementdone are as follows:(1)In terms of limit equilibrium method,two improvements were made based on “the Goodman-Bray method” and “the method improved by China Institute of Water Resources and Hydropower Research”.1)The division of the sliding zones and the toppling zones should be popularized so as to apply to the situation of slope failure in multi-toppling zones and multisliding zones.2)Improving the previous method,of which the direction of shear resistance of the interface is uniform.And dividing the left and right side of the block in to 4 types,which are(1)sliding block-sliding block,(2)sliding block-toppling block,(3)toppling block-sliding block,(4)toppling block-toppling block.Determining the direction of interface shear resistance according to the deformation compatibility and relative movement of adjacent blocks.(2)Two methods are used to calculate "Hoek-Bray classic example",and the results of two methods are compared and analyzed.This prove the correctness of improvement point 1.(3)By using the ameliorated limit equilibrium method,the sensitivity analysis of the five main parameters affecting the toppling damage was conducted according to the "Hoek-Bray classic example".The five parameters are(1)bottom slip surface friction angle,(2)side surface friction angle,(3)bottom slip surface dip,(4)block step height,(5)block width.Defining the relationship between slope safety factor and these five parameters(4)The "example of slope in multi-slide and multi-toppl area" is established by generalizing a bank slope,based on the actual geology.Two methods are used to calculate the "example of slope in multi-slide and multi-toppl area",and the results of two methods are compared and analyzed.These prove that the improved method can be used for slope stability analysis which has multi-slip zones and multi-toppling zones.(5)Using the ameliorated limit equilibrium method,the stability analysis of three typical sections in the actual engineering project "Left spillway slope of Nanta River" was conducted on the slope before the slope collapse and after the precaution measure of cutting slope.The results show that:the safety factor of the three sections before the treatment is generally small,and it satisfy the stability requirements after reinforcement.(6)Selecting one typical section,simulating the deformation of the whole process of slope excavation and reinforcement by UDEC,and analysing the calculation result.The simulation results are in line with the site conditions,and reminds attention to the stability of the lower rock mass in the excavation process,so as to avoid the occurrence of slumps and unnecessary losses.(7)The safety evaluation of the slope before and after the treatment was conducted and the treatment measures proposed by the design were analyzed and evaluated,considering the stability analysis results by limit equilibrium method and the deformation analysis results by using UDEC software as well as reference to the real situation of collapse.