Research On Health Diagnosis Method Of Earth-rockfill Dam Based On POT And Improved D-S Theory Of Evidence

Among the nearly 100,000 reservoir dams built in China,a large number of projects are in different degrees of dangerous working conditions,among which earth-rockfill dams account for the largest proportion.Using health diagnosis technology to quantitatively evaluate the health condition of earth-rockfill dam can effectively and accurately identify various uncertain factors affecting the safety of earth-rockfill dam,timely diagnose the risk degree of earth-rockfill dam,and ensure the long-term safe operation of the dam.The types of health diagnosis information for earth-rockfill dams are diverse and the diagnosis process is complex,so health diagnosis method is the key problem to realize health diagnosis information fusion and safety state analysis of earthrockfill dam.Therefore,in this paper,comprehensive utilization of numerical calculation,safety monitoring,inspect,test and other health diagnosis information,built the importance analysis model of influencing factors on health of earth-rock dam based on fuzzy best worst method and entropy weight method,A method for developing health diagnostic indicators for earth-rockfill dam based on the POT model was established.On this basis,an improved D-S evidence theory and a comprehensive health diagnosis method based on the theory were proposed to provide a scientific quantitative assessment method for the specific and comprehensive health diagnosis of earth-rockfill dam.The specific research contents are as follows:(1)Based on the operating environment and structural characteristics of earth-rockfill dam,according to the theory of earth-rockfill dam break and risk analysis,This paper excavated the influencing factors of the health of earth-rockfill dam,summarized the influencing factors of the health of earth-rockfill dam,and constructed the qualitative and quantitative health diagnosis system of earth-rockfill dam,which provides a structural basis for the subsequent health diagnosis of earth-rockfill dam.(2)The fuzzy best and worst method and entropy weight method were used to determine the subjective and objective weights of each influencing factor in the health diagnosis system,and the Level Difference Maximization method was used to optimize the optimal combination weight.Then the FBWM-EWM-LDM combination weight model was established,which can quantitative evaluate the importance of the factors affecting the health of earth-rockfill dam,and provide a new scientific and effective method for the study of the importance of the factors affecting the health of earth-rockfill dam.(3)based on the requirements of water conservancy codes and the research results of the health status assessment standard in the field of hydraulic and civil engineering,the five-level division principle of the health evaluation grade of earth-rockfill dam structure was proposed.And according to the non-monitoring data and monitoring data information in the diagnosis system,This paper adopted equal interval division method and POT model respectively to construct the comprehensive formulation method of the health diagnosis index of earth-rockfill dam,and establish the division standard of the five-level health state interval,which provide a reasonable and accurate evaluation basis for the health diagnosis of earth-rockfill dam.(4)Aiming at the problems of fuzziness and randomness in the health diagnosis of earthrock DAMS,the D-S evidence theory is improved by using the qualitative and quantitative transformation ability of the extension cloud theory.At the same time,the information fusion criteria are improved by taking the importance of influencing factors and the support degree of diagnostic information as the synthesis rules.Based on the improved D-S evidence theory,the health diagnosis method of earth-rockfill dam was proposed,which solves the problem of the fusion of fuzzy and random multiple evidence bodies and improves the accuracy of the health diagnosis of earth-rockfill dam structures.