水流挟沙力公式的理论剖析与检验

Theoretical analysis and test of sediment carrying capacity formula

为提升河流动力学学科水平,给学术研究及工程应用选取水流挟沙力公式提供依据,本文系统回顾典型水流挟沙力公式的研究进展,针对各公式依据的原理、推导过程、技术细节、影响因子等环节进行阐释分析,指出其亮点与不足,修正了水流挟沙力的定义。结合大量实测资料检验和公式适用性的评价,发现尽管资料率定能提高公式精度,但对于理论有缺陷的公式却不能体现河床和水流的自动调整作用。进一步分析认为,张红武挟沙力公式合理地将挟沙效率系数与水流阻力系数作为综合系数处理,能避免不少公式存在的水流挟沙力同水流阻力呈正比的理论错误,并通过挟沙系数为c(a+bS_(v))^(m)的形式,体现了不同大小含沙量对挟沙效率的影响,能够保证公式具有普遍的适用性和高精度。

In order to improve the discipline level of river dynamics and provide theoretical basis for academic research and engineering application to select the formula of sediment carrying capacity of water flow.This paper systematically reviews the research progress of classical sediment carrying capacity formulas in China,meanwhile,explains and analyzes the principles,derivation process,technical details processing,data calibration and other links of each formula,which points out the highlights and shortcomings of each formula and corrects the definition of sediment carrying capacity of flow.Based on the test of the measured data of the Yellow River and the Yangtze River,the applicability of the formula is evaluated by the graphical verification method and statistical indicators.It is found that although the data calibration link can improve the overall calculation accuracy of the formula,the formula with theoretical errors cannot reflect the automatic river bed adjustment function of the actual river.Further theoretical analysis shows that the reason why Zhang Hongwu’s sediment carrying capacity formula is in the best agreement with the measured data is that the sediment transport efficiency coefficient and the flow resistance coefficient are reasonably treated as a comprehensive coefficient,which avoids the theoretical error that the flow sediment carrying capacity is proportional to the flow resistance in many formulas,and expresses the influence of different sediment concentrations on the flow sediment carrying capacity through the term c(a+bS_(v))^(m),which can ensure that the formula has high calculation accuracy under large water and sediment conditions.