Planning-design Methods And Case Study On Major Drainage System Using Urban Roads

Urban major drainage system is an important part of multi-objective stormwater system of sponge city and urban drainage and waterlogging integrated system,but the relevant planning and "late" norms of the standard,the planning and design guidance of the city's major drainage system is still insufficient,compared to developed countries,China's drainage and waterlogging integrated control system and the related research of construction of major drainage system is still deficient.For the two aspects of major drainage system in "storage" and "drain","drain" research is relatively insufficient,especially the road major drainage system planning and design methods.Therefore,it is necessary to carry out long-term research on the comprehensive planning of the major drainage system,the design method,the hydrological and hydraulic analysis,the storage combined facilities and many other aspects.The key point of this study is the construction of urban major drainage system.First of all,it further clarifies the concept of major drainage system,constitution,sort out the composition of major drainage system and sponge city-related subsystems of the convergence relationship,summarize the planning ideas of the major drainage system and the road planning method for the urban major drainage system,analysis of new and old city,construction points of different terrain city drainage system through literature rieview,comparative study,hydraulic calculation and experiment case assistance and other methods.Aiming at the design method and safety evaluation of road drainage system.The main contents of this paper and related conclusions are as follows:(1)This paper puts forward the design method of the overland roadway path,and determines the drainage area of the flood control design based on the analysis of the waterlogging risk.The total runoff of the catchment and the maximum discharge volume of the drainage system are calculated.This leads to the need for exclusion of the runoff of the surface overland roadway path,then requires repeated check and design adjustments for the road or ditch section,design of the slope until the design standards to meet the requirements;(2)This paper presents a design method based on the coupling between the design flow of overland roadway path and storage facilities,using the calculation method of surface confluence and the calculation process of multi-functional flooding process to carry out the process line of inflow and outflow of storage facilities within the rainfall time.Reasonable design of overland roadway path and storage facilities are used to achieve a comprehensive regional high waterlogging prevention and control standards;(3)According to the stability analysis of pedestrian in the water flow,considering the different working conditions,the risk standard of overland roadway path is determined as the flow velocity * the water depth.When road become overland roadway path,the pedestrian safety through the hydraulic calculation and model experiment is concluded that the value of the flow velocity * the water depth is between 0.33 ~ 0.46 m~2/s;(4)Considering the most unfavorable conditions under various conditions,determined the critical flow rate of pedestrian instability is 0.3~0.54m~2/s through drainage flow velocity * water depth.When the road surface drainage flow rate * water depth is 0.3 m~2/s,the pedestrian in a low risk area,higher than 0.54 m~2/s in a high risk area,between this two values,the pedestrian would be in the middle dangerous area due to different status.According to the calculation and experiment data,the flow velocity and water depth curve are established,and the four hazard level ofoverland roadway path is established.This standard can provide scientific reference for traffic safety warning,urban flood control and flood area planning;(5)Finally,supplemented by practical cases,the planning and design method ofoverland roadway path is introduced,which provides more scientific ideas and technical route for the planning and design of urban major drainage system and related standard.