Ecological Environmental Impact Assessment of Dam Failure Based on Combined Weighting‐Expandable Cloud Coupling Model

Abstract Reservoir dam failure is a kind of sudden and highly harmful disaster, and the comprehensive assessment of the severity of dam failure is an important part of dam risk assessment and risk management, and the current research on the ecological environmental impact of dam failure is obviously insufficient. According to the characteristics of reservoir dam failure, the main ecological environmental impact of reservoir failure is analyzed, and on the basis of systematically collecting the data on the consequences of reservoir dam failure, an index system and quantitative method for the assessment of the ecological environmental impact of reservoir failure are established, aiming at the fixed weight of the index that is artificially set subjectively in the traditional comprehensive evaluation of the consequences of dam failure, and the incompatibility between the value of the evaluation index and the evaluation grade standard, based on the existing laws and regulations and industry norms, the principle of minimum information identification is used to optimize the weight of the index. According to the characteristics of dam‐break environmental factors, a comprehensive evaluation model based on combination weighted extension‐cloud coupling is constructed by using the advantages of extension to solve incompatibility problems and cloud model to deal with randomness and fuzziness. The model is applied to the reservoir. The results show that: 1) After the optimization of the minimum information identification principle, the index weights obviously balance the subjective and objective weights, and the obtained comprehensive weights solve the problem that the subjectivity and objectivity of the indicators cannot be well unified, which is more in line with the actual engineering needs; 2) The comprehensive assessment level of the ecological environmental impact of reservoir failure is basically consistent with the evaluation level calculated by other evaluation models, and the degree of differentiation is better, which shows that the proposed model has good practicability, and provides a new method for the comprehensive assessment of the ecological environmental impact of dam failure.