Study On Characteristic Of Dam Disaster Complex Adaptive System And Model For Dam Break Threshold Value

There are more than 8.7 million dams in China and about 3.7 million of these dams face serious safety problems. The threat of dam to social stability, economical development, and ecological security is larger along with the rapidly economic development. Thus, studies on characteristic of dam disaster complex adaptive system and dam break threshold value have great theoretical and practical significance to dam safety operation and risk control.The scientific problems such as characteristic of dam disaster complex adaptive system, disaster inducing factors analysis, and dam break threshold value are studied based on the theoretical methods and technical means of structural mechanics, hydrology, multivariate statistical analysis method, and risk analysis technology. The conceptual model of dam break disaster complex adaptive system is built which reveals the characteristic of dam disaster system and interactional mechanism of disaster inducing factors. The model for dam break threshold value is built based on dam risk analysis. It provides the basis and reference for dam safety management. The study mainly including the following contents:(1) Interactional mechanism of dam disaster inducing factors was analysed. In view of the characteristics of abundance information and dynamic of dam break, the dam failure database system (short for DFDS) has been constructed. The correspondence analysis method was applied to reveal the relationship of disaster-causing factor, disaster-pregnant environment, and disaster-bearing body. The cluster analysis method was used to classify the dam failure disaster into four categories: extraordinarily big accident, major accident, serious accident, and ordinary accident.(2) The characteristic of dam break disaster was researched based on complex adaptive system. Most traditional dam risk analysis methods cannot fully consider complex, dynamic, and uncertain situations of dam system. In this research, dam system was conceived as a complex adaptive system, in which dam safety was perceived as a phenomenon that resulted from the interactions among disaster-causing factors, disaster-pregnant environment, and disaster-bearing body that influence or are influenced by regulatory activities within the dam system. The dam safety evaluation method based on the CAS theory was proposed. The simulation platform, called SWARM, is enhanced and applied for modeling dam system safety. Then the dynamic evolution process of dam safety was obtained. The method provides theoretical foundation for revealing interactions of disaster inducting factors.(3) The model for dam failure threshold value was built. The risk analysis model inducing by the three factors of overtopping, seepage, and bank slope instability were studied. The threshold value was acquired using the relationship formula between risk probability and dam type. The reliability of the method was verified.(4) The Dongwushi reservoir located in Hebei province of China was taken as a case study. The dam risk and threshold value induced by overtopping, seepage, and bank slope instability were studied. The results provides theoretical basis for dam safety operation.