基于城市内涝数值模拟的设计暴雨雨型研究

以南昌市青山湖排涝片区为研究对象,从典型暴雨的选择入手,结合现行规范要求,分析了不同典型暴雨的放大方法以及水利部门"综合雨型"的优缺点,应用MIKE软件模拟不同设计暴雨雨型对城市排涝过程的影响。通过对泵站开机负荷、主要控制断面的水位和流量等情况的对比分析,提出城市内涝防治体系设计暴雨雨型计算方法的选择建议。研究结果表明,同倍比放大法虽然便于应用,但其主要统计时段降雨量的重现期差异很大,难以客观评价市政排水与流域排涝系统的能力;同频率放大法能够控制主要时段的"同频",但其时间刻度需要细化,调算过程较为复杂,而且不同典型暴雨同频放大条件下的排涝过程差异较大;"复合雨型"可以兼顾城市排水与流域排涝系统的能力复核,雨型生成过程相对简单,便于应用。

Design Rainstorm Patterns Based on Numerical Simulation of Urban Flooding

Taking Qingshan Lake drainage area of Nanchang City as the research object,starting from the selection of typical rainstorm,combined with the requirement of the current code,the advantages and disadvantages of different amplification methods of typical rainstorm and“comprehensive rainstorm pattern”proposed by water conservancy bureau were analyzed,and MIKE software was applied to simulate the influence of different design rainstorm patterns on urban drainage process.Based on comparative analysis of pump station load,water level and flow hydrograph of the main control sections,suggestions on the selection of design rainstorm pattern calculation method for urban flooding control system were proposed.Although the same ratio amplification method was convenient for application,it was difficult to evaluate the capacity of municipal drainage and regional drainage system objectively.The reason was that the return period of the rainfall in the main statistical period varied greatly.The same-frequency amplification method could control the same frequency of the main periods,but its timescale needed to be refined and the adjustment process was complex.Moreover,the drainage process of different typical storms amplified with the same frequency was quite different.The“composite rainstorm pattern”took into account the ability check of municipal drainage and regional drainage system,and the generation process of rainstorm pattern was relatively simple,which was convenient for application.