Scenario-based Simulation Of Heavy Rain In The Urban Area Of ​​Shanghai And Its Impact On Roads And Subways

With the trend of global warming,extreme precipitation weather continues to increase,and the resulting flooding disasters also tend to increase.As a complex system that closely interacts with nature and population and economic social activities,the city is not only the center of human activities and socio-economic development,but also the region most affected by rain and flood and the highest risk.Therefore,the city’s torrential rain scenario simulation has become a hot issue in current urban risk researchWe have selected the center of Shanghai,which has a developed economy and dense population,as the research area.Pearson-III probability calculation method,floatarea model method,and scenario simulation method were used to simulate the 2~hour storm rainfall process based on the latest rainstorm model in Shanghai based on the Chicago rain pattern;and to use the high-precision DSM urban digital terrain in downtown Shanghai The data and land use data were combined with the drainage data of the downtown area of Shanghai,and a simulation of the internal rainstorm in the central city area was performed for 2 hours in floatarea.The accuracy of the simulation results was verified by the data of the collected water points.Based on this,the simulation results were used to analyze the impact of rainstorms on the roads and subway stations in the downtown area.The research results can not only provide a basis for the rational planning of urban roads and subway stations,but also provide reference for disaster prevention and mitigation of urban water disasters.Main research conclusions:1.In the 2-hour precipitation process,combined with the rainfall and rainfall distribution characteristics of the Chicago Rainfall type,the maximum time period for the accumulated water area is 45min~60 minutes.During this period,the unit rainfall intensity is large and the water is accumulated in a short time.Difficult to discharge.In the following 10 years and 10 years,the area of accumulated water was smaller during the following return period,and the area of accumulated water was larger in the 50 years and 50 years,and the high value area of the depth of the water was evenly distributed.In the 90min~105 minute period,the area of stagnant water decreased compared with 45min~60 minutes.However,due to low altitude and poor drainage in some areas,the depth of accumulated water in some areas showed an increasing trend,but in general the depth of accumulated water depth was high.The area is decreasing.2.In the case of a five-year encounter in three years,the downtown area is less affected by heavy rainfall storms,which basically does not affect traffic travel;when the situation occurs in 10 years,water accumulation in some areas reaches more than 15 cm.Heavy rains will cause inconvenience to residents.In the case of a 200-year encounter in 50 years,heavy rains will have a huge impact on the urban system,especially in the 200-year scenario,which will cause a large amount of water in the community to be more than 30 cm.And road water is more than 20 cm,and heavy rain will cause huge damage to the city.3.Depth of water depth at the return period of 10 years and 10 years is mainly distributed in the areas where the depth of accumulated water is large,mainly in the areas along the banks of the Suzhou River,in the northwest of Putuo District,and in the north of Yangpu District,and only in other regions.A very small number of scattered distributions,which are also roughly consistent with the data distribution of the collected water points verifying the simulation accuracy in this paper.In the 50-year and 50-year-above periods,the area of high-water plots has expanded,and Xuhui District also has large areas of high-value water distribution along the Huangpu River area and parts of Hongkou District.4.Putuo District will be taken as an example in the event that in 50 years and more than once in 50 years,rainstorms will have an important impact on road traffic.When the 200-year return period is reached,the length of the section of stagnant water over 30 cm will increase,which may affect most of the roads in Putuo District.At the same time,there are also a large number of roads with water accumulations of more than 30 cm in some communities.Caused old-style residential water intake and other risks.5.In the following 10-year and 10-year return periods,there is no risk of water in the subway station in the downtown area of Shanghai;when the rainstorm return period is more than 50 years or more than 50 years,the storm Infighting may lead to the risk of water in some subway stations.In the 200-year scenario,there may be as many as 16 influent stations.The influent stations are mainly distributed in low-lying areas such as the banks of the Suzhou River and some sinking.Squares such as People’s Square.