城区内涝条件下城市公交-地铁双层交通网络的脆弱性分析

为提高城市公共交通应对内涝的能力,利用复杂网络理论的Space-L方法构建了武汉市中心城区的地铁、公交无向加权网络,并在此基础上运用ArcGIS软件构建了不同耦合半径的公交-地铁双层交通网络,确定了连边的权重和节点的重要度,计算了静态下地铁网络、公交网络和不同耦合半径的公交-地铁双层交通网络的介数、平均路径长度和聚类系数等复杂网络特性指标;针对内涝导致的单一站点失效和多站点失效情况,以最大联通子图比例、网络连通率和网络效率为指标进行了故障模拟,分析了节点故障与连边故障对城市公交-地铁双层交通网络脆弱性的影响。结果表明:城市公交-地铁双层交通网络的最大联通子图比例、网络连通率和网络效率3项指标在攻击下的下降程度和下降速率都低于单一地铁网络和公交网络,城市公交-地铁双层交通网络的抗毁性能高于单一交通网络;对比节点故障与连边故障发现,节点故障下网络的脆弱性更大。

Vulnerability of Two-layer Traffic Network of Bus and Subway under Waterlogging Condition Based on Complex Network Theory

In order to improve the ability of urban public transport to cope with waterlogging,this paper uses the SpaceL method of the complex network theory to build an undirected weighted network of bus and subway in the downtown area of Wuhan.On this basis,the paper uses ArcGIS software to build a two-layer traffic network of bus and subway with different coupling radiuses,and determines the weight of edges and importance degree of nodes,computes the complex network characteristics of subway network,bus network and two-layer traffic network with different coupling radiuses under static conditions,i.e.betweenness,average route length and clustering coefficient,etc..Aiming at the single site failure and multi-site failure caused by waterlogging,the paper carries out fault simulation with the maximum connectivity subgraph ratio,network connectivity rate and network efficiency as indicators,and anlyzes the influence of node failure and edge failure on network vulnerability.The results show that the degree and rate of decline of the three indicators of the two-layer traffic network are lower than that of the subway network and the bus network,and the damage resistance of the two-layer traffic network is higher than that of the single network.By comparing node failure with edge failure,it is found that the network vulnerability under node failure is greater than that under edge failure.