长历时暴雨强度公式的推求方法

近年来,随着极端暴雨事件的出现,导致城市内涝灾害频繁发生,原有降雨历时仅为2h的市政排水设计暴雨强度公式已无法满足城市暴雨设计的需求,因此就要延长暴雨采样历时,推求出长历时(24h)暴雨强度公式。针对以上问题,根据北京市提供的52a(1961-2012)原始降雨资料并进行数字化处理,结合水利的长历时特点,采用兼顾市政排水,水利排涝,内涝防治的采样方法,应用P-Ⅲ分布曲线进行频率分析后采用6种经典方法推求暴雨强度公式的参数值,优选出误差最小且满足规范要求的暴雨强度公式参数值,进而推求长历时暴雨强度公式,在此基础上与短历时暴雨强度公式比较,分析两者的差异,为城市雨水排除规划设计提供科学依据和参考。

Derivation method for long-duration storm intensity formula

In recent years,with the emergence of extreme storm events which cause frequently urban waterlogging disasters,the original municipal drainage design storm intensity formula for only two-hour rain duration could be unable to meet the needs of urban storm design,therefore the sampling storm duration should be extended and long duration(24hours)storm intensity formula should be obtained.To solve the above problems,according to original rainfall data of Beijing for 52years(1961—2012),which is digitally processed,combined with long duration of the characteristics of water conservancy,through the integrated sampling approach of municipal drainage,water conservancy drainage and waterlogging prevention,P-Ⅲ distribution curve is used for frequency analysis and six classical approaches are used to obtain the parameter values of storm intensity formula.The optimal parameter values meeting standards requirements with minimum error are selected,then the derive longduration storm intensity formula is obtained,which is compared with short-duration rainfall intensity.The difference between them is analyzed,which provides a scientific basis and reference for the planning and design work of urban storm water drainage system.