任意坡面上均匀沙起动概率及起动流速的计算公式

Threshold probability and incipient motion velocity of uniform sediment on arbitrary slopes

基于概率统计理论,引入泥沙颗粒组成及相对暴露度产生的附加质量力,得到了任意坡面上泥沙起动概率的计算公式;并将其引入到泥沙起动研究中,从理论上推导出了任意坡面上近底作用流速及垂线平均流速公式;此外,公式还可以进一步简化为弯道岸坡、顺直岸坡、正负坡以及平坡条件下的泥沙起动流速公式。通过任意坡、弯道岸坡等条件下的实测资料验证,本文公式计算值与实测数据符合较好,可应用于任意条件下泥沙起动流速的计算。

Based on the probability theory and statistics knowledge,the influence of additional mass forces produced by sediment gradation and relative exposure degree are considered,and the sediment threshold probability formula on arbitrary bed slope is deduced. Furthermore,sediment threshold probability is introduced to study on sediment threshold conditions,and the formula of sediment incipient motion velocity on arbitrary bed slope is derived theoretically. In addition,the simplified formulas on the riverbank slope,positive and negative slope,and flat slope are also deduced. Validation shows that the calculation results in this study are in good agreement with the observed data,and can be used to calculate incipient motion velocity both on combined transverse and longitudinal sloping beds.