Study On The Evacuation Of Terrorist Attack Induced Hazardous Materials Transport Accidents

It has an important role that to determine the evacuation scope and emergency resources allocation of the hazardous materials accident which caused by terrorist attacks in the process of transportation. The hazardous materials transport accident caused by terrorist attacks has a instantaneous feature compared with the accident happened in usual condition. Also, it will cause a huge psychological panic for society. It constructed an evacuation scope model of different accident scenarios in the case of terrorist attacks based on the instantaneous leak Gaussian diffusion model, vapor cloud explosion model and BLEVE fireball dynamic calculation model.Considering the characteristics of terrorist attacks, it introduced a panic coefficient to improve the models. Through a simulation, it finds that the scope of evacuation of leakage approximates an elliptical shape at any moment, but the effect scope approximates to a balloon section after a period of time. Furthermore, the lateral diffusion distance that perpendicular to the wind direction increases first and then decreases. Because the impacts of wind speed, the diffusion distance of leakage gas along the wind direction is much larger than the others. The scope of evacuation of explosion and fire is a rounded distribution. Further analysis results find that the blast overpressure and thermal radiation dose show a diminishing power law relation with the distance to the accident center. The results show that leakage has the largest scope of evacuation. The evacuation scope of explosion and fire is small, and there is no obvious difference between them. By comparative analysis, it find that the evacuation scope under the terrorist attacks condition is larger than common condition. The panic amendatory area becomes smaller by the reduction of the degree of injury. The feasibility of the model proposed in this paper is validated.For the assignment of vehicles between emergency vehicles supply points and evacuation points, the allocation of person between evacuation points and emergency shelters and the optimal path selection during the evacuation progress. It constructed an emergency resource allocation model for evacuation which aimed at the shortest total time to evacuating.The constraints contain the number of emergency evacuation vehicles, as well as the evacuation persons and the capacity of emergency shelter. It applied the Dijkstra algorithm to search the shortest path between each vehicles supply point and each evacuation point, as well as the shortest path between each evacuation point and each emergency shelter based on the network graph. It simplified the network through deleting the sides and nodes that not belong to shortest paths and transformed the problem to a multi-source and multi-sink minimum-cost maximum-flow problem. Through a case to verify the feasibility of the model and algorithms built in this paper. The results show that the minimum cost obtained in the model does not equal to the actual evacuation time, the actual evacuation time is the maximum cost among all evacuation paths, but the assignments of vehicles between emergency vehicles supply points and evacuation points and the allocation of person between evacuation points and emergency shelters are the optimal solutions.