Research On Vulnerability Of Hazardous Materials Road Transportation Network Based On Cellular Automata

As rapid economic development has made China the world’s second largest economy,the scale of energy chemical industry in China is constantly expanding.Transportation demand of hazardous materials is increasing as well.Hazardous material is strongly destructive and easy to spread and cause secondary hazards.Once a transportation accident occurs,it will be a direct threat to people’s lives and property,bringing enormous pressure to road traffic and administrative department of production safety,and resulting in adverse social impacts.The hazardous materials road transportation network(HMRTN)is an important carrier during the whole transportation process.Its stability and reliability are the prerequisites for ensuring hazardous materials road transportation(HMRT)safety.Effectively identifying key nodes in the network and rationally arranging emergency traffic assignment are prerequisites to scientifically prevent and mitigate HMRT disaster.Exploring the vulnerability of HMRTN is conducive to reducing the damage of network failure and scientific planning and management of road transportation.By combining the complex network theory,cascading failure theory and cellular automata theory,this thesis aims to reduce the vulnerability of HMRTN.To begin with,from the perspective of HMRT and complex network,the characteristic parameters and network types are thoroughly explored.And combined with the basic characteristics and assumptions of the previous method of constructing the network,the structural model of HMRTN is established.Secondly,based on the cascading failure model of HMRTN,the node state attributes are subdivided.And the joint effect of the node failure degree and the node recovery rate is considered to establish a cascading failure model of HMRTN based on cellular automata theory.Finally,taking HMRTN in Dalian as an example,the reasonability and accuracy of the model are verified.The research shows that the cascading failure model of HMRTN based on cellular automata theory is feasible and applicable,and can truly describe the variation trend of the vulnerability of HMRTN in Dalian.As the failure coefficient increases,the HMRTN vulnerability decreases.Especially,when the failure coefficient exceeds a certain threshold value,its increase will no longer reduce the vulnerability of the network.And while other parameters remain unchanged,the vulnerability of the network decreases as the node recovery rate increases.This model can identify the key nodes of HMRTN in Dalian as well.In the network protection process,nodes with high vulnerability should be emphasized.For the attack strategy,the network vulnerability is lower under the tightness attack strategy than that under the node degree and betweenness attack strategy.For the traffic assignment strategy,the effect of the Degree Distribution(DD)allocation strategy is the least satisfactory,and the Surplus Load Distribution(SLD)allocation strategy should be preferentially selected to effectively reduce the vulnerability of the network.