基于概率分布优选的水电工程施工初期导流风险率估计

Estimation of Diversion Risk Rate at Initial Stage of Hydropower Project Construction Based on Probability Distribution Optimization

科学准确地评估水电工程施工初期导流风险率为施工导流方案决策提供了重要依据。以往风险模型中施工洪水洪峰的随机分布均假设服从P-Ⅲ分布,这会影响导流风险率的精度和可靠性。首先采用K-S检验法对初拟的施工洪水洪峰概率分布类型进行初选,并通过RRMSE、M MAE、QQD值的拟合优度综合评比优选最佳概率分布;然后综合考虑水文、水力随机性,构建基于概率分布优选的施工初期导流风险率计算框架,并给出采用Monte-Carlo方法求解风险率的具体流程;最后对国内两座大型水电工程实例进行应用分析。结果表明,风险率计算框架及求解流程是可行的、有效的;I-MED具有一定的拟合能力,可用于导流风险模拟;两个案例的概率分布排序不同、最佳概率分布不同,进而影响导流风险率大小。研究结果有效拓展了施工导流风险理论框架。

Scientifically and accurately estimating diversion risk rate at the initial stage of hydropower project construction provides an important basis for decision-making of construction diversion scheme.In previous risk models,the random distribution of construction flood peak is assumed to follow P-Ⅲ distribution,which will affect the accuracy and reliability of diversion risk rate.The K-S test method was used to select the preliminary probability distribution type of construction flood peak.And then the best probability distribution was selected through the goodness of fit evaluation of RRMSE,MmA and QQp values.Considering the randomness of hydrology and hydraulics,the calculation framework of diversion risk rate at the initial stage of construction based on probability distribution optimization was constructed,and the specific process of solving the risk rate using the Monte-Carlo method was given.Finally,two large hydropower projects in China are applied and analyzed.The results show that the proposed risk rate calculation framework and solution process are feasible and effective;I-MED has certain fitting ability and can be used in the simulation of diversion risk;The probability distribution order of the two cases is different,and the optimal probability distribution is different,thus affecting the diversion risk rate.The research results effectively expand the theoretical framework of construction diversion risk.