Vulnerability Analysis Of Arterial Networks Focusing On Risks Of Long-distance Bridges And Tunnels In Megacity

With the increase of traffic congestion problems and the rise of traffic accident rate,scholars from domestic and foreign countries have paid great attention to the vulnerability of road network.Because of the large scope and variability of vulnerability,there is still no comprehensive and reasonable indexes for road network vulnerability.Large bridges and tunnels,which are very important links that connect the whole road network,draw especial attention from experts and the public.The safety of large bridges and tunnels is widely considered,but there is a lack of researches for bridge and tunnel vulnerability.To solve problems in the existing evaluation model of traffic network vulnerability,a comprehensive evaluation model that integrated complex network and topological potential was proposed in this thesis.First,the urban road network was abstracted into a complex network topology based on complex network theory.Network attributes,which could influence vulnerability of traffic network,were extracted.Second,the influence range of traffic was analyzed on the basis of the network radiation model and congestion propagation theory.Finally,vulnerability indexes of traffic network were defined.Vulnerability of bridges and tunnels in the entire traffic network were assessed from physical attributes of roads,traffic conditions,and topological characteristics of traffic network.Results show that(1)abstracting the traffic network into a complex network is a high-efficiency processing method,whereas the combination of the network radiation model and congestion propaganda theory overcomes not only dependence of the gravity model on adjustable parameters during traffic assignment but also difference brought by parameters.Thus,the traffic assignment is objective and the results are accurate.(2)Determining the value of influencing factor is important.Physical attributes of roads ? traffic attributes and structure attributes of traffic network can directly affect the value of influencing factor accurately.The evaluation becomes accurate when a large number of influencing attributes are considered.The comprehensive evaluation model integrating complex network and topological potential can evaluate vulnerability of the traffic network effectively.The model provides a new perspective and method to study vulnerability of the traffic network.