希尔兹曲线统一表达式及其在唐家山堰塞湖下游河道冲刷防治中的应用

An Uniform Formulation of the Shields Diagram and Its Application in the Scouring Prevention of Tangjiashan Barrier Lake Downstream Channel

在研究地震堰塞湖泄洪导致的下游河道冲刷问题时,所涉及的一个最基本的问题就是泥沙颗粒起动的问题。在泥沙起动切应力的研究中,希尔兹曲线无疑是一个经典并且已经被水利工作者广泛使用。但是由于希尔兹关系曲线中,纵、横坐标都包含摩阻流速,因而实际应用中会很不方便。主要是要建立一个希尔兹曲线的确切表达式,以便解决希尔兹曲线使用困难的问题。表达式是通过一个经验公式的形式给出的,公式首先要求是连续函数,在大小沙粒雷诺数情况下其能自动简化为传统公式,且在整个沙粒雷诺数变化范围内其能够与实验数据吻合,作者模型与其它已存模型比较结果显示作者模型具有最好的精度。最后将作者模型应用于唐家山堰塞湖下游河道冲刷防治中。

The incipient motion of sediment is very important in exploring the mechanism of scouring induced by the dam break.An empirical formulation of the Shields diagram for incipient motion of sediment was developed,which was approximately equal to the traditional formula for very large and small Re＊ c,respectively.Compared with other formulas and experimental data,this formula fits experimental data best and the formula structure also can be acceptable.Finally,the model was applied in the scouring prevention of Tangjiashan Barrier Lake downstream Channel.