坡面径流下泥沙起动临界水深研究

Research on the Critical Water Depth of Sediment Starting under the Slope Runoff

在对斜坡上泥沙颗粒受力分析的基础上,引入相对暴露度的概念,采用滚动模式推导出了斜坡上单颗粒泥沙起动的临界条件,并结合径流-渗流耦合模型进一步推导出了斜坡上泥沙起动临界水深表达式,该表达式表明临界水深的大小主要与泥沙自身的物理性质、坡度和相对暴露度有关。当Δ’取紧实排列时,表达式适用坡度范围为0~30°。并通过实测资料对公式的有效性进行了验证,结果表明在粒径为10 mm以下该公式的计算值与实测值接近,精度较高;同时存在一个"分界粒径",超出该粒径值,计算值与实测值二者的相对误差将显著增大。

Based on the stress analysis of sediment particles on the slope and by introducing the concept of relative exposure,the critical condition of single particle sediment starting on slope is deduced by the rolling mode,combined with the runoff-seepage coupling model,the critical water depth expression of sediment incipient motion on the slope is further derived.The expression shows that the critical water depth is mainly related to the physical properties of sediment itself,slope and relative exposure.When the Δ' is tightly arranged,the slope range of the expression is 0~30°.The validity of the formula is verified by the measured data.The results show that the calculated value of the formula below 10 mm is close to the measured value and the accuracy is high.At the same time,there is a"boundary particle size",which exceeds the particle diameter value,and the relative error between the calculated value and the measured value will increase significantly.