Study On Optimization Of Route Selection Of Public Multi-objective Emergency Refuge In Chemical Accidents

In recent years,with the rapid development of economy,the number of industrial parks or projects involving flammable,explosive,toxic and harmful substances has increased significantly,and major chemical accidents have also occurred frequently.Once an accident occurs,emergency evacuation is the main measure to reduce accident losses and casualties,and the choice of evacuation path is the most important decision type in evacuation model.Unlike previous path planning problems,major chemical accidents may have adverse effects on the health of residents in affected areas because they are exposed to subsequent extreme phenomena(e.g.,fallout,toxic clouds,thermal radiation,overpressure or debris).At the same time,considering the temporal and spatial characteristics of accident injury,it is a trend to establish dynamic multi-objective optimization model.However,the solution method of the model and its application in emergency decision-making need to be further studied.Dijkstra algorithm is a classical algorithm to solve the shortest path problem.In recent years,many scholars began to focus on the development and application of improved Dijkstra algorithm to solve the dynamic shortest path and multi-objective optimization problems,but few people discussed whether Dijkstra algorithm can solve the dynamic multi-objective optimization problem.In addition,in order to evacuate the public in the affected area as soon as possible,the number of evacuees has to be considered.On the premise of large evacuation scale,how to ensure the lowest evacuation cost? This can be similar to the minimum cost maximum flow problem in network flow theory.But in the past,the algorithm based on network flow is usually based on the static network.The combination of augmented path algorithm and shortest path algorithm is a common and effective method to solve the problem of minimum cost and maximum flow.But for dynamic network,the feasibility of this method needs further discussion In view of the above problems,the specific research contents of this paper are as follows:(1)This paper analyzes the consequences of major chemical accidents by consulting domestic and foreign literatures,and establishes a dynamic multi-objective optimization model of route selection for evacuation,which maximizes evacuation number,minimizes expected dose,minimizes evacuation time,and minimizes route complexity.(2)By studying and discussing the main mathematical characteristics of the dynamic multiobjective optimization model based on the weighted sum method,the improved Dijkstra algorithm and the minimum cost maximum flow algorithm based on the network flow theory are proposed to solve the evacuation model,and an example is analyzed.(3)Combining ALOHA accident simulation software and GIS system,the feasibility of evacuation model and method is discussed.By studying the impact of local refuge and evacuation as public protection action in reducing individual risk and group risk,how to formulate emergency protection action to reduce accident loss and casualties is analyzed and discussed.