基于网络负载容量模型的城市路网级联失效研究

Study of Urban Road Network Cascading Failure based on Network Load Capacity Model

在城市道路交通中,关键路段的失效可能导致路网的大面积拥堵,为了准确判断城市道路交通网络的关键路段,首先采用原始法构建城市道路交通网络的几何拓扑图,并在已有的交通网络级联失效模型基础上,考虑了城市道路网络的有向性和拥堵的局部扩散特性,对模型的初始负荷定义及失效负载重分配的规则进行了改进,并采用改进后的模型对不同路段破坏失效进行了模拟分析,研究了不同路段发生破坏后拥挤的扩散过程.采用破坏影响后的路网平均距离降低比例和失效路段所占比例来反映路段的破坏程度,最后对路网中的路段进行重要度排序,并结合路段在路网中的度、介数及级联失效的影响程度等指标,利用K-Means聚类分析对路段进行了聚类.结论表明:只考虑路段上的流量大小或路段的一些静态指标并不能够准确判断路段的重要度,路网中往往还存在一些潜在的重要路段,考虑多种指标对不同路段进行聚类更具合理性.

The failure of key segmentsinurban traffic networkmay causelarge traffic congestion.In order to determineaccurately the key segmentsof urban road traffic network,the geometric topology graphofurban traffic network was constructed by the original method.Based on the existedcascadingfailuremodel of traffic network,the definition of initial load in the model and the rules for redistribution of failure load were improved in consideration of the orientation of urban road trafficnetwork and the local diffusion characteristics of traffic congestion.The improved model was applied to examine the diffusion process of congestion after different segmentswere damaged due to the simulation and analysisof the failure of different segmentsafter being damaged.In addition,the ratio of the average distance reduction of the road network after beingdamagedand the proportion of the failureroad segments were used to reflect the destruction influence of the road segment.Finally,the importance of the road segments in the road network was sorted,and the road segments were clustered byusing the K-Means cluster analysis combiningthe degree,the betweennessand the influence degree of the cascade failure in the road network.The experiment results show that only considering the traffic flowor some static indexes of the road segment cannot accurately determine the importance of the road segment as there are often potential important segmentsin the road network.It is more reasonable to consider multiple indicators to cluster different road segments.