| Cascading failure is a common phenomenon in urban traffic network.In urban road traffic network and urban rail transit network,there is often a node and congestion in a certain section,or after natural disasters,the fault and congestion are transmitted to adjacent nodes or roads through the coupling relationship between traffic networks,resulting in large-scale congestion.Therefore,it is necessary to study the congestion diffusion phenomenon of nodes in urban traffic network.By studying the congestion diffusion mechanism of nodes,it is necessary to take certain measures to control the nodes with high importance and reduce the loss caused by cascade failure.The main research contents of this paper are as follows:(1)The capacity load model is introduced in detail,and the initial load,the determination method of failure load and the evaluation method of cascade failure impact range are determined.(2)A section of the actual road network in Dalian is selected to study the diffusion process of congestion with the failure time after the node failure with medium and high value in the road network.The important nodes in the road network are determined by the proportion of congested sections caused by the node failure,and some measures are taken for the nodes with high importance.(3)The measures to prevent cascading failure are divided into two types: preventive measures before failure and solutions after failure.Preventive measures this paper introduces a node expansion strategy to prevent large-scale cascade failure by expanding the capacity of important intersections.Solution measures this paper proposes the section impedance increase strategy and intersection closure strategy,which can reduce the impact of cascade failure by changing the impedance of congested sections after node failure and closing some nodes.Finally,the comparison before and after the improvement measures will be taken to prove the effectiveness of the measures. |
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