Study On Rock Mass Quality And Deformation Failure Mode Of Right Abutment Slope Of Rumei Hydropower Station In Tibet

With the rapid development of hydropower construction in our country,the stability problem of high slope is becoming more and more serious,it caused by the construction of hydropower station under the complex geological environment in the high mountain gorge area.This paper is based on the field investigation and detailed geological data.The right dam shoulder slope rock structure of Rumei Hydropower Station in Tibet Lantsang is descripting of detailed.The deformation characteristics of slope rock mass and slope under different working conditions are analied of comprehensiving with geological survey,deformation of structural plane types and characteristics,and analysis of rock strength and the slope rock structure network model is built based on the discrete element method UDEC.The classification of rock mass slope deformation and failure mode are studied,and the combined calculation of slope rock mass structure network model is established to calculate the stability coefficient of the potential sliding surface of the model was evaluated on the slope stability of transfer coefficient method,through the above system the research work,the main results are as follows:(1)By the detailed description of the structural surface of the slope at the scene,on the basis of the principle of engineering geological analysis,the qualitative analysis of engineering geological grading is proceeded from the engineering geological characteristics of structural plane and engineering geological significance.Geological characteristics of the engineering structure uncertainty level III and IV are obtained.The mathematical statistics of structural engineering geological features are carried out.The rock mass structure of the right abutment slope is mainly composed of steep dip fault,unloading fissure and gently dipping random structural plane.(2)According to the detailed investigation on the typical slope adit at the scene,the quality of the slope rock mass is evaluated qualitatively by combining with the single factor index of rock compressive strength,the rock quality and the structural plane spacing.By using BQ method,RMR method and CSMR method,the quality of rock mass on the slope is evaluated quantified.Finally,the main type of the slope rock mass quality is determined.(3)According to the typical distortiondestruction phenomenon on the surface and flat cave,the qualitative analysis of the deformation and failure mode of right dam shoulder slope the slope is carried out.The main deformation and failure modes of the slope is slipping tension along the inclined surface of structure fracture,along the tension crack,unloading crack block the collapse,unloading tension crack,compression and creep,shear deformation and fracture of extrusion and rupture.It provides a basis for evaluating the slope instability mode.(4)Based on the development degree of the structural plane and spatial distribution,the probability distribution of structural plane about is analyzed statistically.The random structural plane network model is generated in software of UDEC by working out the corresponding program.The typical rock mass the structure of the network model of the right dam shoulder slope is obtained to combinate with fault structure,unloading cracks,dikes and other deterministic surface coupling.(5)Based on the two-dimensional discrete element software UDEC,the deformation and failure mode of the slope is simulated by a simplified processing of the network model.By comparing the numerical simulation results with the qualitative analysis,the main deformation and failure mode of the slope is shear slipping-tension cracking.The stepped deformation failure path is mainly composed of combination with steeply tectonic facets and slow dip facets.(6)Based on the calculation results of the discrete element method,the calculation model of the stability coefficient of the potential sliding surface is established.the stability of slope is analyzed by the transfer coefficient method.The results show that the stability coefficient of the slope is greater than 1 in the case of natural,heavy rain and earthquake,and the slope is in a stable state.In the case of earthquake and rainstorm,the local destabilization of slope may be destroyed.When the slope is excavated,the stability coefficient decreases in the case of the natural,rainstorm and earthquake,but it is more than 1,and the slope is stable.In extreme cases,the slope may be unstable.