Social And Environmental Impact Assessment Of Dam Break Based On Variable Fuzzy Sets Theory

Dam risk management system includes two parts:risk probability and risk consequence evaluation.The former research was carried out earlier and the results were relatively rich,while the latter research started late and is still in a slow stage of development.It is urgent to further strengthen the research of dam risk consequence evaluation.Life and property losses,social and environmental impacts constitute the main content of dam-break consequence evaluation.The research on life and economic losses started earlier.At present,the related research results at home and abroad are relatively rich,while the research on social and environmental impacts is significantly scarce.This paper relies on the National Natural Science Foundation of China’s Natural Science Foundation project"Watershed Cascade Reservoir Collapse Model and Risk Early Warning Basic Theory Research"’(51579208),the variable fuzzy set theory is introduced to study the social and environmental impact assessment of dam failure,aiming at the multi-factor uncertainty in dam risk consequence assessment.The main achievements of this paper are as follows:(1)This paper briefly introduces the progress of the dam failure evaluation field at home and abroad,and sorts out the main content and characteristics of the dam failure evaluation.It elaborates the source and developnment of the variable fuzzy set theory,and combines the membership function and relative difference function.The basic principle of the theory is expounded,and the evaluation steps of tlhe variable fuzzy comprehensive evaluation model and the determination methods of each index are given,which lays a foundation for the application of the following examples.(2)Considering the characteristics of dam break and its complexity,uncertainty and fuzziness,this paper refers to the existing research results,combines the relevant concepts of social and environmental impact assessnment of dam break,and established a social impact assessment index system for dam breaks based on parameters such as risk population and economic aggregate,and an environmental impact assessment index system for dam breaks based on parameters such as river pattern and water environment.The standard system clarifies the nature and meaning of each quantitative parameter and qualitative parameter,and establishes a five-level evaluation standard from slight to very serious.(3)Based on the theory of variable fuzzy sets,the social impact and environmental impact assessment models of dam break are established.The above models are applied to the risk consequence assessment of Liujiatai Reservoir and Shaheji Reservoir respectively.The evaluation results are compared with those based on set pair analysis,fuzzy grey theory and fuzzy mathematics theory.The results show that the variable fuzzy set evaluation model is adopted.The evaluation results are accurate and reasonable,and have good practicability.It provides a new scientific thinking and method for dam risk and consequence evaluation.