Research And Application Of Hydrodynamic Numerical Simulation For Urban Rainstorm Flood

With the rapid development of the national economy and the acceleration of urbanization,the urban rainstorm flood disaster has caused widespread concern in the world.When the city experiences high intensity rainfall,due to the inadequate drainage capacity of urban drainage system,it often floods parts of the city,leading to severe floods.In recent years,urban rainstorm flood disaster is becoming more and more serious,which not only seriously endangers the life and property safety of urban residents,but also restricts urban economic and social development to a certain extent.According to the relationship between city rainstorm and flood,facing the increasingly serious city flood disaster,simulating the submergence process and area,exploring and adopting scientific city rainstorm flood simulation method,providing the basis for the decision-making of urban disaster prevention and reduction,it has very important research significance and practical application value.First of all,on the basis of predecessors' research and practice,this paper introduces the features of urban rainstorm floods,summarizes the influence of urbanization on rainstorm flood,introduces the urban rain flood simulation technologies and common urban rain flood models from the perspective of hydrology and hydraulics respectively,and elaborates this article research significance and the main content.Secondly,this paper discusses the basic principles of the HydroInfo basin multidimensional coupling model and verifies the precision and accuracy of solving the dendritic channel network,looping river network,drainage pipe network,two-dimensional model,lateral coupling and longitudinal coupling problems by using HydroInfo software.The main difference between the urban topography and the topography of natural river basin is that there are a lot of buildings and other obstacles in the city,which will have a great impact on the evolution and propagation of the flood.This paper verifies the reliability of the three methods of grid cells with buildings top elevations,solid wall boundaries and grid cells with artificially increased roughness to deal with the water blocking effect of buildings.The accuracy of the results calculated by the three methods is compared and analyzed through the measured values of model tests.Finally,on the basis of collecting the topographic,hydrological and meteorological data of the area in Chengdu's downtown area,this paper deduces the regional design storm and river design flood process in the study area.This paper generalizes the buildings in the area by grid cells with artificially increased roughness method,and introduces the method implemented in the HydroInfo software.Finally,using the 24-hour design storm process and the P=2% design flood process as boundary conditions,a one-and two-dimensional coupled urban rainstorm flood model was established.By analyzing the process of flood evolution and submergence,the simulation results are reasonable,which shows that it is feasible to use HydroInfo software to simulate urban floods in the city within a large area,the underlying surface is very complex,and it can provide reference for the relevant departments of flood control decision-making.