南京市短历时设计暴雨雨型研究

Study on design of rainstorm pattern based on short duration in Nanjing City

设计暴雨的确定是城市管网系统排水能力规划设计的重要基础。以南京市中心城区为研究区,首先应用暴雨强度公式分别计算历时60 min和120 min的不同重现期设计暴雨量,再基于1982-2015年降水资料利用年最大法选取得到年最大降雨序列,并计算综合雨峰系数,最后应用Pilgrim&Cordery雨型和芝加哥雨型推求南京市中心城区历时60 min和120 min的设计暴雨过程,并对峰值大小、雨峰位置、雨峰出现时累计暴雨量进行对比分析。结果表明:历时60 min和历时120 min设计暴雨的雨峰分别处于整场降雨过程的1/2时间和前1/3时间;两种方法得到的雨峰值大小相当; Pilgrim&Cordery雨型法计算的雨峰出现时累计暴雨量大于芝加哥雨型法;短历时设计暴雨雨型推荐选用芝加哥雨型。研究成果可为南京市中心城区地面积水风险评估与排水管网系统的规划和建设提供参考。

The determination of design storm is an important foundation for the planning and design of urban flood protection and drainage projects.The paper takes the central area of Nanjing City as the research area.First,the storm rainfall intensity formula was used to calculate the stormwater volume at different recurrence periods of 60 and 120 min,respectively.Then the annual maximum rainfall sequence was selected based on precipitation data from 1982 to 2015 and the synthesized rain-peak modulus was calculated.Finally,the Pilgrim&Cordery pattern and the Chicago rain pattern methods were used to deduce the design storm process lasting 60 min and 120 min in the central area of Nanjing,and the peak size,rain peak position and accumulated rainfall before the rain peak were compared.The results showed that the rainstorm peaks of 60 min and 120 min are at the time of 1/2 and the first 1/3 of the whole rainfall process,respectively.The rainfall peak values obtained by the two methods are not significantly different.The rainfall calculated by Pilgrim&Cordery pattern when the peak appeared is larger than that of the Chicago pattern.The Chicago pattern is recommended for the short duration design storm.The research results provide a reference for the urban waterlogging risk assessment and drainage and waterlogging prevention project planning and construction in the central area of Nanjing.