The Research On The Design Standards And Risk Analysis Of Urban Storm Water Pipe Network

In the urban drainage, the determination of design standard affects the ability of resisting the rain and the cost of the rain facilities. In recent years, abrupt change of climate have caused the time of flood peak appeared in advance. The speeding up of urbanization have made the impervious area magnify. However the low design standards of urban rainwater drainage system result in insufficient drainage capacity. It is easy to form water when a large storm hit the city. In order to reduce the occurrence of waterlogging, this paper studied the design standard of urban rainwater pipe network and its risk analysis.Firstly, in this dissertation, the current research in the design standard and risk analysis of urban rainwater pipe network in mainland and overseas are reviewed. This paper have a systematic analysis of design standard, including planning design method, design return period and runoff coefficient.Secondly, the theory and methods of risk analysis are introduced. According to the operation characteristic of the pipe network and the technique support of the modeling, the functional risk coefficient and hours of overload are used to be risk index. Then sensitivity analytical method and comprehensive fuzzy method provide techniques to obtain a semi-quantitative assessment of the operation risk of the rain pipe network. Then it will be applied to an instance.In the end, a case of some study area in Hefei is given. By establishing the model of pipe networks, we illustrate the whole process of the rainwater pipe network simulation and risk assessment. Besides, the new network is designed based on the advice of the design standard, and evaluated by use of the present method. According the result of hydraulic simulation and risk evaluation, the suggestion on urban rainwater pipe network design standards which this paper put forward is feasible and effective.