Study On Simulation Model Of Waterlogging In A City Under Extreme Rainstorm

With the acceleration of the urban process,the change of the underlying surface of the city makes the impermeability coefficient increase,and the flood peak is in advance,and the peak flow increases,and the water is accumulated in the city,which seriously threatens the urban safety.And the city's rainwater drainage network drainage capacity and urban demand capacity imbalance,increasing the risk of the possibility of occurrence.In this paper,the rainwater drainage network in a city of Chongqing is taken as the research object.Based on the modeling tool Mike Urban,the simulation is carried out.Then simulation the return period about 3 years,5 years and 50 years.And analysis these indicators.The flow of the catchment area,the pipe-filling,the pipe-flood,the distribution of urban water and other indicators to determine whether the drainage capacity of the drainage network in line with the relevant provisions,and according to the calculation results estimate the Waterlogging area,combined with the "Sponge City" implementation plan,the study area to increase the diameter of pipe,the construction of reservoirs,the construction of rainwater storage facilities and other engineering measures,to control the flood.once again simulation the model after the implementation,Analyze the effectiveness of the implementation of engineering measures.The main contents and achievements of this paper are as follows:1.This paper analyzes the causes of urban waterlogging from two aspects: natural factors and human factors,and analyzes the current situation of urban water and water research at home and abroad and the current situation of urban drainage network system in China.2.Aiming at the method and principle of model construction,this paper puts forward a complete method to establish urban drainage pipe network model,such as processing data,parameter rate control,pipe network generalization,catchment area division and connection,and to improve the condition of lack of measured data,The parameters of the rate of use and calibration methods,to a certain extent,to ensure the accuracy of the model;3.Based on the simulation of the drainage network in a city in Chongqing,based on the rainstorm formula of the study area,the rainstorm scenarios with different return periods were synthesized by using the Chicago process line.The return period was 3years,5 years,50 year of the drainage pipe network operation,and concluded that thedrainage network in the region does not meet the "Outdoor Drainage Design Code" in the relevant provisions of the conclusions should be carried out to reduce urban water.4.Combined with the "sponge city" for the city of waterlogging prevention and control related content,based on the "low impact development" concept of urban waterlogging control,and put forward several effective transformation measures.According to the successful implementation of the transformation measures,the simulation results show that the depth of the area is obviously reduced and the overflow range is obviously reduced.