Seismic Safety Evaluation And Maximum Aseismic Capability Research Of Concrete Face Rockfill Dams

The Maximum seismic capacity of concrete face rockfill dam is an important index to evaluate uie safety and stability of face rockfill dam.In recent years,with the continuous development and utilization of water resources and the progress of water conservancy development,the number of dams located in the strong earthquake area in northwestern Southwest China has also been increasing.Therefore,it is of great significance to study the dynamic response of concrete faced rockfill dam,the stability of dam and the ultimate seismic capacity.In this paper,taking Xiaoyou pumped storage power plant downstream rockfill dam as an example,the seismic time history analysis of 6 combinations of 3 artificial seismic waves by checking earthquake and the most unfavorable combination are used to study the ultimate seismic capacity.Slope stability,seepage control of the panel,residual deformation of the earthquake and the stress of the panel,the seismic safety and ultimate seismic capacity of the rockfill dam are evaluated.The main work of the dissertation is as follows:1.The static and dynamic calculation of the three-dimensional nonilinear static and dynamic finite element analysis program CFRD.f of self-developed face rockfill dam is carried out.The static part simulates the gradual construction and staged water storage process of the dam.The constitutive relation of rockfill materials adopts the Duncan E-B model,and the nonlinear finite element equation solves the problem of using the midpoint incremental method.Dynamic part,the time-history analysis method is used to analyze the nonlinear seismic response.The dynamic constitutive relation of rockfill material is equivalent viscoelastic model.Considering the effect of hydrodynamic pressure of reservoir on the dynamic response of the panel dam,The dam body permanent deformation,the use of circular arc sliding surface,and through the grid and automatic incremental search to calculate the instantaneous minimum slope slip safety factor for each moment.2.The three-dimensional finite element model of rockfill dam is established,and the results of stress and deformation of the rockfill body and panel during the construction period and the normal storage level are obtained,which provides the basis for the dynamic calculation of the normal water level.3.Under the condition of normal water level of concrete face rockfill dam,the dynamic calculation of three kinds of three-dimensional dam body with 6 kinds of combination of artificial seismic waves of earthquakes is carried out to study the dynamic calculation results of dam body and panel,Dynamic response and distribution of joints,and seismic stability analysis of dam slope and concrete slab at the same time.4.By inputting different levels of bedrock peak acceleration,analysis and evaluation of the reservoir dam under the ultimate seismic capacity.5.The research results show that under the effect of seismic check,the slope of rockfill dam of Xianyou Pumped Storage Power Station is stable;the deformation and deformation of the dam are good;the deformation of the dam accords with the general rule;besides the tensile stress of the panel Besides,the distribution of the residual stress is also in accordance with the general law,and the joint displacement is within the range that can be accommodated by the water stop structure and material.According to the analysis results,the dam is safe under the check earthquake conditions.0.45g is the calculated maximum seismic capacity of the next reservoir dam.