考虑洪水过程随机性的多维联合设计洪水风险分析

Risk analysis of multi-dimensional joint design flood considering the randomness of flood process

设计洪水是水利工程规划设计的重要工作,为工程规模确定和风险管理提供依据.针对传统单变量同频率和同倍比方法的局限性,以分层Archimedean Copulas函数为基础,构建了考虑整个洪水过程特性的多维联合设计洪水风险分析模型.以多变量联合重现期为防洪标准,采用蒙特卡洛与Copula函数相结合的方法随机模拟洪峰和不同历时的洪量的设计洪水组合,以实测典型洪水过程为依据,采用变倍比法放大洪水过程,得到设计标准对应的洪水过程线.以长江流域某水库为例,分析研究校核洪水位存在的风险.相对于传统同频率和同倍比计算方法,多维联合设计洪水风险分析模型充分考虑了洪水事件的随机性,以及整个洪水过程变量之间的相关性,为水库设计与安全运行提供参考.

Design flood,an important basis for the planning and design of water conservancy projects,is provided to determine scale and risk management of project. Considering the limitations of the traditional univariate the same frequency or the same ratio method,a multi-dimensional joint design flood risk analysis model considering the character of the whole flood process is established to analyze the risk of different design flood level in this paper. Taking the joint return period as the design standard,the multi-dimensional joint design flood between flood peaks and floods of different durations are simulated with the method of combining Monte Carlo and Copula functions. The design flood process is calculated with the typical flood process using different scaling ratio based on the measured typical flood process. A reservoir located in the Yangtze River basin is selected as an example,and the corresponding check flood levels of reservoir are computed with reservoir operation regulation using these design flood process and analyzed the corresponding risk. Compared with the same-frequency and the same ratio methods of univariate distribution,the uncertainty of flood event and the correlation between their variables are considered,it could provide a reference for the design flood and safe operation of the reservoir.