Study On Disaster Chain Of Typhoon And Its Impact On Urban Lifeline System Vulnerability

Natural disasters have always been major global problems faced by human society.For coastal cities,typhoon is a natural disaster with high frequency,wide range of influence,strong damage and heavy loss.The urban lifeline system is the guarantee of the normal operation of the city,the study of the evolution characteristics of the urban lifeline system under the typhoon disaster is of great significance to improve the disaster prevention and mitigation ability of the urban lifeline system.In this paper,typhoon disaster chain and its impact on the vulnerability of urban lifeline system are systematically studied.The main research work is as follows:(1)This paper analyzed the impacts of typhoon hazard factors on the vulnerability of seven urban lifeline systems,such as power supply,water supply,drainage,communication,gas supply,oil supply and transportation systems,as well as the impacts of the failure of each subsystem caused by typhoon hazard factors on the vulnerability of other systems,and constructed the disaster chains of urban lifeline system caused by typhoon.(2)Based on the complex network theory,the disaster events in the typhoon disaster chains of urban lifeline system are regarded as the nodes of the network,and the triggering relationships between the disaster events are regarded as the edges of the network.The disaster chain network of the urban lifeline system caused by typhoon is established,and threee node parameters of the network and three edge parameters of the network are selected to quantify the network characteristics of the disaster chain.(3)Based on the characteristics of disaster chain network,the risk assessment model of disaster chain is constructed by using the probability of disaster occurrence,the event loss and the vulnerability of network edge,and the risk mitigation factor is introduced to improve the risk assessment model.Among them,the probability of disaster occurrence is obtained according to the statistics of the probability of triggering between the disaster events in the cases of historical typhoon in the city.The loss of the event and the vulnerability of the network edge are calculated by the node parameters and the connection edge parameters in the disaster chain network respectively.The risk mitigation factors are determined by the experts' scores on the disaster prevention and mitigation ability of the lifeline system.(4)Taking Shenzhen City as example,the risk of its urban lifeline system under typhoon disaster is evaluated.The results show that: the damage of power facilities,tree lodging,poor drainage and other disaster events have a great impact on the disaster evolution process,which is basically consistent with the results reflected by the historical typhoon cases in Shenzhen;after considering the effects of risk mitigation,the risk of each disaster chain has decreased significantly,which shows that the current urban lifeline system in Shenzhen has a strong ability of disaster prevention and mitigation.Finally,according to the actual situation of Shenzhen City,in view of the damage of power facilities and other disaster events that have a great impact on the evolution of the disaster,the corresponding countermeasures and suggestions for chain-cutting and disaster reduction are put forward.