暴雨内涝情景下城市路网通行效率变化与修复策略——以郑州7·20暴雨灾害为例

The Traffic Efficiency Evaluation of Urban Road Network before and after the Rainstorm Disaster and Its Repairing Strategy:A Case Study of the 7·20 Rainstorm Disaster in Zhengzhou

测评城市交通运转效率、识别关键枢纽路段,对于提升城市韧性、增强城市应对极端天气或突发事件的能力具有重要意义。文章在空间句法模型基础上构建了一种新的城市路网运转效率评价方法,从“全局—局域”“穿行性—集成性”综合集成的视角评价了郑州7·20特大暴雨灾害前后的路网效率变化情况,开展关键节点识别和故障路段修复次序的优化研究。结果表明:①文章所提出的路网效率评价方法能够有效刻画城市道路网综合运转状态,定量评估网络节点失效对路网运转性能的影响程度。②交通网的受损将影响到交通流的重新分配,导致交通流分布与沿线设施的关联度下降。灾后交通运转效率的降低是绕行行为增加、路网集成能力减弱、局部出行行为减少以及交通流与沿线设施分布不匹配综合作用的结果。③根据路网效率恢复弹性可对比择优不同的修复策略,确定关键节点的修复次序,位于主干道上的半阻断点较之位于次干道上的全阻断点宜被赋予更高的优先级。

Evaluating urban traffic operation efficiency and identifying key hub sections play an important role to make city robust for extreme weather or emergencies.Based on the spatial syntax model,this paper proposes a new evaluation method of road network efficiency from the perspective of"global-local"and"through movement-to movement",calculates the performance of road network before and after the 7·20 Rainstorm Disaster in Zhengzhou,and conducts the study of key nodes identification and optimization of restore order.The results show that:1)The method proposed in this paper is effective,which can objectively evaluate the efficiency of road network,and access the impact of node failure on the running state of urban traffic.2)The damage of the traffic network will affect the redistribution of traffic flow,leading to a declined correlation between traffic flow and the facilities nearby.The reduction of traffic operation efficiency after the disaster is due to a combination of things,including the detour behaviors,the weakened integration capability of road network,the local movement reduction and the mismatch between traffic flow and facilities along the line.3)The resilience can be used in the optimization of different repairing strategies and the sequence setting of key nodes to be restored.It is considered that the fault points on the main roads where vehicles can get through slowly should be given more priority than the fault points on the feeder roads where vehicles can't get through completely.The results are helpful to the optimization of road network and the improvement of urban traffic emergency management.