Risk Analysis And Assessment Of Wuhan Roads Under Rainstorm And Waterlogging Disaster

In the context of global climate change and urbanization,coupled with the lagging in the construction of drainage and waterlogging prevention infrastructure,many cities in China have shown a trend of“waterlogging when rainstorm occurs”.Urban roads are extremely vulnerable under the rainstorm and waterlogging disasters,because they are not only the most regular flooded areas,but also important channels for runoff.Moreover,the urban road network is an important guarantee for normal operation of various urban systems and the daily life of residents.Once roads suffer from rainstorm and waterlogging disasters,both residents and the city will be negatively affected.By sorting out literation and data about rainstorm and waterlogging disasters,urban roads and natural disaster risk,the urban road risks under rainstorm and waterlogging disasters in this paper were divided into three types:risk of road flooding,risk of road traffic congestion and generalized risk.And the downtown of Wuhan was taken as the research area to conduct risk analysis and assessment of urban roads under rainstorm and waterlogging disasters.The main research of this paper is as follows.(1)Urban rainstorm and waterlogging simulation and analysis of the risk of road flooding.Base on the analysis of rainstorm waterlogging process,the GIS based rainstorm inundation model was used to simulate the runoff and confluence under rainstorm.And the rainstorm waterlogging process in Wuhan was simulated in three return periods:10-year,50-year and 100-year.The simulation results were proved to be reliable by comparing it with the waterlogging points in Wuhan over the years.After that,the flooding data on roads was extracted and the risk of road flooding was analysed from the maximum flooding depth and the flooded length of road.(2)Traffic simulation and roads congestion analysis under rainstorm and waterlogging.In this paper,Xudong area of Wuhan was taken as the simulation area and the traffic simulation was carried out by using Trans CAD.And the OD matrix of the study area was reversed by the OD backstepping method based on traffic status data of Amap.Base on the inverse OD matrix and stochastic user equilibrium method for segmental traffic distribution,the traffic flow distribution of the roads network is obtained.On the basis of rainstorm and waterlogging simulation,whether the flood road section can pass or not was judged according to the road flood safety standard.Then the road network under rainstorm and waterlogging with 50-year return period and 100-year return period was rebuilt.The redistribution of its traffic flow was obtained by using Trans CAD.Finally,the road congestion risk was determined in terms of road traffic saturation.(3)Combined with road flooding hazard and road vulnerability,a road generalized risk assessment model under rainstorm and waterlogging disasters was built based on the generalized risk theory.Considering the social and economic factors,the road complex centrality and functional importance were selected.The generalized risk of road under the rainstorm and waterlogging with 100-year return period was evaluated after the normalization of indicators and the determination of weights.The results show that the overall risk of road network in Wuhan is relatively high.Qintai Avenue,Parrot Avenue,Hanyang Avenue,Linjiang Avenue and Xudong Avenue and some other roads are high-risk while there are few low-risk and lower risk road sections.