Under The Action Of Reservoir Water Kam Screen Level In The Left Bank Of The Reservoir Engineering Slope Stability Research

The Jinping Grade I Hydropower Station is the first stage of the development of five cascaded hydropower stations in the lower reaches of the Yalong River,where the water energy resources of the main stream of the Yalong River are most enriched.However,the left bank slope of the reservoir area has developed a toppling deformation rock mass,and the left and right bank slopes have been deformed under the excavation of the project.The deformation of slope can be induced by the collapse deformation,especially the softening of the faults outside the slope,especially the softening of the rock mass in the lower part of the slope.The stability of toppling deformable slope is one of the most concerned problems in engineering construction,but there is still no simple and accurate method to evaluate its stability.In view of the above problems,this paper takes the left bank slope in the reservoir area of Jinping I Hydropower Station as an example to analyze its deformation and development characteristics under the condition of collecting a lot of original geological data,and establishes a model according to the actual geological profile.The parameters of the model are obtained from the high pressure permeation experiment,and the simulation results are compared with the actual monitoring conditions.Finally,the conclusion of deformation and stability change of toppling body under the action of reservoir water is obtained.Based on engineering geological analysis and rock mechanics,combined with experimental and numerical simulation,this paper mainly studies the following:(1)analysis of the slope structure characteristics,the slope deformation signs in the front of the dam,analyzed its forming conditions and influencing factors.(2)on the basis of dump deformation development characteristics,different lithology dump level is obtained by high pressure filtration experiment of rock mass permeability coefficient.(3)the dump slope deformation in the process of water storage,in seepage field,stress field characteristics,based on the fluid-structure interaction theory working condition of each right before the dam slope stability coefficient and the relationship between the water level change research.(4)based on the monitoring data of displacement change,the actual scene investigation and simulation analysis finally concluded that dumping body in a variety of deformation of the slope under the action of reservoir water and stability.Finally,the following conclusions are drawn.(1)the permeability of natural rock mass without structural plane is sandstone,marble and slate.However,the permeability of rock mass increases gradually with the increase of the inclination angle of the structural plane,and the permeability of rock mass reaches the maximum when the rock mass is close to failure during the whole process of the rock mass being destroyed under the confining pressure.There will be a stage of decline after the destruction,and then the penetration rate will rise again.(2)the underground water level of the slope increases with the rise of the reservoir water level,but at the early stage of the rise,the infiltration line is almost parallel to the top of the slope because the water is not fully infiltrated into the slope.The maximum deformation value and range of the slope also increase with the increase of water level.The area with the largest deformation appears in the slope foot area and the middle and upper part of the slope body,and the deformation in the middle part of the slope body may promote the instability of the sliding surface controlled by the large boundary condition of the slope body.During the sudden drop of water in the reservoir,the infiltration line of the surface of the slope also decreases rapidly,and the infiltration line of the front edge of the slope is larger than that of the rear edge,but because the decline is not large at this time,the water is still infiltrating into the body of the slope,such as faults in areas with better permeability.At lamprophyre vein,the water level is obviously higher than that of other media,the displacement of slope towards river bed is not obvious and the range of maximum value is small,and the displacement value of slope towards river bed is changed to some extent.However,the maximum value of settlement displacement is almost unchanged,but the range of maximum value is increasing.It is preliminarily determined that the pore water pressure generated in saturated rock mass in the region of water level variation is not dissipated when the reservoir water level drops suddenly.It will cause the seepage force outside the slope and increase the deformation of the slope.(3)the calculation results of slope stability under fluid-solid coupling show that the slope stability coefficient under natural condition,rainstorm condition and natural earthquake condition is higher than that of 1.11(M-P method)and is in stable condition only under heavy rain earthquake condition.The stability coefficient of slip surface 1 is slightly lower than the minimum standard of slope stability in type A project area.The occurrence of accidental condition in water storage should be paid attention to and the corresponding support treatment should be made for the rock mass above the sliding surface in time.(4)from the point of view of qualitative analysis,the monitoring data show that the apparent displacement curve of the slope under the control of large boundary conditions is basically convergent with the stability of the simulation.In quantitative analysis,except for the difference between the value simulation of displacement in Y direction and the actual monitoring,the simulation results are in good agreement with the actual monitoring results.