Research On Vulnerability Of Road Network Under Urban Waterlogging

The stability of urban road traffic network is an important guarantee for residents' living needs and social development.However,the frequent occurrence of rainfall and waterlogging has a serious impact on the normal operation of urban road network.This paper establishes the comprehensive evaluation index system and the double layer evaluation model based on the theory of road network vulnerability,and the actual waterlogging problem in a certain area of She nzhen City was evaluated.In view of the impact of rainfall and waterlogging on urban traffic,this paper analyzes the three aspects of traffic speed,road traffic capacity and traffic volume generation.Based on the GPS data of Shenzhen Taxi,the traffic speed reduction during daytime and night,peak hours and different grades of roads in light rain and heavy rain was analyzed.Based on the SP survey data,the effect of rainfall waterlogging on residents' travel behavior was analyzed by MNL model,and the calculation model of traffic generation quantity of various traffic modes in different weather was established.Based on the analysis of the impact of rainfall and waterlogging on the traffic system,the concept of road network vulnerability under the cond ition of rainfall and waterlogging is established.Based on the effectiveness index of topology,the robustness index of road network performance and the network efficiency index of traffic demand are selected,and the comprehensive evaluation index system of vulnerability is established.In this paper,a two-layer model of road network vulnerability assessment is established,the upper layer is vulnerability and the probability of flooding in the low lying area,and the lower level is the stochastic user equilibrium model.A case of waterlogging in a certain area of Shenzhen City,the three aspects of road network vulnerability were evaluated from the three scenes of waterlogging with heavy rain,small rain and no rain.Several low-lying and easy-to-water areas in this area were analyzed and calculated,and the road network vulnerability index of each area was determined,so as to provide decision makers with the transformation or management advice.