鸭绿江下游年最大流速概率分布选型及参数估算

Probability Distribution Model Selection and Parameter Estimation of Maximum Annual Current Velocity of Downstream Yalu River

随着洪水灾害研究的不断深入和防洪减灾工程措施逐渐完善,洪水流速决定洪水携沙能力和动力强度成为水灾的主要因素逐渐被突显出来。本研究以鸭绿江下游荒沟站实测38年最大洪水流速(PMV)为样本,以曼宁公式为理论基础,根据基本断面稳定性、糙率变化等因素判定样本具有一致性且满足独立样本条件;根据洪水流速特点及概率分布特征判定样本服从皮尔逊-Ⅲ型分布。利用适线法对其参数进行估计,并计算不同频率最大可能流速,开展对洪水年最大可能洪水流速的定量计算研究,为防汛减灾提供技术支撑。

With the deepening of floods research and the gradual improvement of flood control engineering,dynamic strength of the flood flow and the notion of flood velocity determining sand carrying capacity are increasingly standing out as the major factors leading to water disasters.In this paper,using the biggest flood flow in 38 aat the Yalu River downstream Huanggou station as sample and Manning′s equation theoretical analysis as basis,it was determined that the sample is consistent and meets the basic requirement for independent sample condition,based on the basic cross-section stability,roughness changes and other factors.It was found that the distribution of the sample obeys Pearson-Ⅲ distribution characteristics,based on the flow rate and the probability of flooding.To conduct quantitative study on annual probable maximum velocity,and to provide technical support for the flood mitigation,fitting method was used to calculate the estimated parameters and the maximum possible flow rates at different frequencies.