Study On Numerical Simulation And Risk Assessment Of Urban Moistureproof Drainage When The Tide And Rainfall Occur Simultaneously

Due to the unique geographic location,the urban areas have suffered from the combined action of the heavy rain and the tide.Most of our country and the global economy are concentrated in the coastal areas.The economic value of coastal cities is high,and once the city is attacked by the urban waterlogging,the property loss and casualties are very serious.So it is very important to study the waterlogging disaster in the coastal cities.Firstly,the paper introduces the progress of urban flood and waterlogging models at home and abroad in recent years.The theory and model of urban water flow numerical simulation are also introduced emphatically at home and abroad research.Secondly,the theory and methods of runoff calculation,confluence calculation and drainage calculation of urban network are discussed respectively.Hydrological knowledge are used to deduce the design of rainfall process,the design of tidal level process.Based on the DEM terrain grids of high precision terrain attribute information,the runoff is calculated according to the method of meticulous runoff generation in urban subarea.The drainage capacity curve of the actual stormwater pipe network is fitted by piecewise linear method,and t-he relationship between drainage capacity and tide function is established.The conditions of model boundary which allow water cross two way are set reasonable model parameters and conditions and ultimately the surface production and flow module,the underground pipe network water dynamic module and the flood module are combined to build the model of City coastal waterlogging,and it was also calibrated to verify the rationality.Thirdly,In this paper,four kinds of urban waterlogging simulations were set up,including four types(tide level process,only rainfall,multi-year and rain encounter,extreme tide rain encounter),and the scenarios were compared and analyzed with each other.And obtain the waterlogging index of urban waterlogging,water depth,and typical position waterlogging duration.On this basis,the urban flood and waterlogging were studied whether the specific situation of Haidian Island waterlogging between different scenarios or no,and from various angles to reveal the city moisture-proof drainage and the difference.Lastly,based on the results of waterlogging simulation,and combining with the characteristics of the waterlogging disaster,this paper constructs the dynamic risk assessment system which based on the scenario simulation results,and finally draws out the Haidian Island risk zoning map.Combining with the above research results,this paper puts forward comprehensive and directive countermeasures.