基于Copula函数的邕宁水利枢纽多时段施工导流风险及方案决策

Risk and Scheme Decision-making of Multi-period River Diversion for Yongning Water Conservancy Project Based on Copula Founction

为了研究不过水围堰多时段施工导流风险问题,提出了基于Monte-Carlo方法和Copula函数的施工导流水文风险计算模型。考虑各导流时段施工洪峰流量之间的相关性,根据实测水文资料选取Copula函数拟合,建立联合分布,采用随机模拟技术生成导流时段洪峰流量并统计风险,进而计算了邕宁水利枢纽二期导流风险,并利用TOPSIS决策模型进行了方案决策。结果表明,联合分布拟合效果良好,能更加合理地分析风险率,且延长至前汛期的围堰挡水方案为该工程的较优方案,带来了巨大的经济效益。

In order to study the risk problem of multi-period river diversion for no-overflow-cofferdam,the hydrological risk calculation model was proposed based on Monte-Carlo method and Copula function.In view of the correlation between peak discharge of floods,the joint distribution was established by the selected Copula function according to the measured hydrological data.The floods of diversion periods were generated by simulation technology and the risk could be obtained.Taking the second-stage diversion of Yongning water conservancy project for an example,the risk was calculated and the scheme decision-making was done by the TOPSIS model.The results indicate that the fitting effect of the joint distribution was satisfactory so that the risk could be estimated more rationally.The scheme that the cofferdam water retaining time was extended to the early flood period was better for this project,which brought tremendous economic benefits.