Deformation-based Seismic Fragility Analysis And Seismic Safety Risk Assessment Of High Earth-rock Dam

Hydropower energy,as a kind of clean energy,compared with traditional power generation,has the characteristics of clean,high power generation efficiency,and low production cost.The southwest of China is affluent in hydropower energy,and a group of high dam repositories represented by high earth-rock dams has begun to be built and operated in this region.However,due to frequent seismic activities and complex geological conditions in this region,high dam repositories have been damaged or even broken under seismic action,resulting in partial or total loss of their original functions,which will be disastrous.From the three aspects of seismic risk analysis,seismic fragility analysis,and seismic disaster loss analysis,systematically study the probability of dam damage or even collapse accidents under the action of seismic,evaluate the downstream impact area for disaster loss analysis,and scientifically and reasonably evaluate the seismic safety of high earth-rock dams,which is of great practical significance to ensure the regular operation of national socio-economic activities and national water resources security,improve the ability to deal with emergency preparedness and standardize the emergency response management system.This paper systematically studies the seismic safety risks of high earth-rock dams from the above three aspects.The main research contents and results are as follows:(1)The seismic fragility of the high earth-rock dam is analyzed,and the seismic damage and failure levels of the high earth-rock dam are divided according to the seismic damage and deformation parameters.In this paper,the Zipingpu concrete-faced rockfill dam is taken as the research object,and the ground motion records were imported into the finite element model for calculation.The dam crest’s maximum horizontal displacement and the dam crest’s maximum seismic subsidence rate were taken as deformation parameters.Based on the nonlinear response and current research results,the seismic damage level of the high earthrock dams is divided.The MSA method draws the seismic fragility curves of high earth-rock dams.The artificial neural network is introduced into calculating the seismic fragility curve,and the PSO-BP-MSA method is proposed.The PSO-BPNN-MSA method calculates the seismic fragility,drawing the three-dimensional seismic fragility surface.(2)The damage effect of seismic is taken as the precondition for dam break accidents in reservoir dams,the disaster loss of dam break consequence is analyzed,and a comprehensive evaluation index system and evaluation model of high earth-rock dam break consequence are constructed.The improved analytic hierarchy process(AHP)based on the cloud model is used to calculate the evaluation index weights,which better solves the deficiency that the subjectivity of experts strongly influences the weight calculation results.The cloud theory is combined with the matter element analysis method to obtain the cloud matter element model,and the comprehensive evaluation of dam break consequences is carried out based on the cloud matter element model.A comprehensive evaluation of dam break consequences was conducted for the Zipingpu concrete-faced rockfill dam.(3)The seismic risk analysis,seismic fragility analysis,and seismic disaster loss analysis are systematically combined,and the seismic safety risk assessment framework and the evaluation standard of seismic comprehensive risk grade of high earth-rock dam are proposed.According to the seismic safety risk assessment framework for the high earth-rock dam,a systematic seismic risk assessment was conducted for the Zipingpu concrete-faced rockfill dam.The results show that the Zipingpu concrete-faced rockfill dam has a low probability of dam break due to seismic and is safe.