Analysis On The Formation And Evolution Mechanism Of Disaster Chain In China’s Barrier Lake

The dammed lake not only affects the personal safety of upstream and downstream residents,but also seriously restricts the development of local economic construction.At present,the researches on dammed lakes at home and abroad mainly focus on five aspects: the causes of dammed lakes,the mechanism of dammed lakes,disposal and risk management,development and utilization,and the environmental effects of dammed lakes,and many achievements have been made.However,directly from the perspective of disaster chain,there is relatively little research on the risk evolution relationship among disaster events in China’s dammed lake disaster chain.Therefore,based on the disaster system theory,this paper analyzes the disaster mechanism of China’s dammed lakes,constructs the disaster chain evolution network of China’s dammed lakes,uses the disaster chain risk assessment model to measure the risk relationship of China’s dammed lakes,and studies the evolution law of dammed lakes’ disaster chains by using complex networks.The specific research contents and results are as follows:First of all,using Houyi collector to crawl the dammed lake cases from related websites to establish a dammed lake case set,and analyze the formation conditions of dammed lake from three aspects: terrain conditions,solid material source conditions and water source conditions.From the perspective of disaster chain,this paper analyzes the disaster mechanism of dammed lake,identifies dammed lake disaster events,analyzes five evolution models of disaster chain from the induced relationship between disaster events,and constructs the evolution network of dammed lake disaster chain in China.Secondly,referring to the chain risk assessment model and combining with the evolution characteristics of disaster chain,the risk assessment model of disaster chain is constructed.The factors that constitute the risk assessment model of disaster chain are: the probability of one disaster event causing another disaster event;Losses caused by disasters;The action intensity of one disaster event causing another disaster event on other disaster events,that is,the vulnerability of the edge;The risk value of disaster chain measured by the previous three indicators.The model is applied to the risk assessment of dammed lake disaster chain in China,and the risk value of any disaster chain can be obtained,so that the risk ranking of dammed lake disaster chain can be realized.Based on this,four modes of chain breaking disaster reduction are put forward.Finally,a complex network model is established by referring to the induced relationship between nodes in the disaster chain evolution network of dammed lakes in China,and the network visualization is carried out by using Gephi software.By calculating the characteristic parameters of complex network,it is recognized that the key disaster-causing factors of disaster chain network are heavy rainfall,landslide,landslide,debris flow,etc.,and important inducing relationships such as landslide →blocking river,dammed lake burst → road damage,heavy rainfall → landslide,etc.By comparing the random network,it is found that the evolution network of disaster chain in China’s dammed lake considering weighting has the characteristics of small world.Finally,according to the identified key disaster-causing factors and important disasterinducing relationships,the idea of chain-breaking disaster reduction is put forward from two angles of primary disaster chain and secondary disaster chain.