确定泥沙沉降率综合经验系数α的方法

An empirical coefficient α in sediment settling velocity

在水利工程沉沙池的设计中，计算泥沙沉降的方法往往采用一维超饱和输沙法，其泥沙沉降车的计算最关键是要确定综合经验系数α。通常，把α近似作为常数，或采用一些经验公式，但只适合某些特殊情况。在一般情况下，α值与泥沙沉速、水深、摩阻流速等有关，是一个变值。现依据山东省打渔张灌区第五条渠的实测资料，采用多元回归分析法，推出求α值的经验公式，并通过方差分析和对回归方程显著性的判断，以及用实测资料对α值验证计算比较后，认为采用多元回归分析法确定沉沙池泥沙沉降车综合经验系数α，不论从理论上或实际应用上都是合理的，得到的求α的经验计算公式是可行的，计算出的泥沙沉降率精度可以满足设计要求。

While designing a sediment settling pool in water conservancy projects,the sediment deposition is usually computed by supersaturated sediment transport method with one-dimensional flow assumptions. The key to computation is to determine the comprehensive empirical coefficient a. In conventional practice a is approximately taken as a constant or is chosen by using some empirical formula;such an a can only be applicable to some particular conditions. But in general a varies with the sediment settling rate.water depth.friction,flow velocity et al. Now based on the prototype data measured in the fifth channel of Dayuzhang irrigation basin,Shandong Province,an empirical formula determining a is derived by multiple regression analysis. Through mean square root deviation analysis and significance test of the regression equation and comparing a with the measured data,it is concluded that this comprehensive empirical coefficient a in sediment settling velocity determined by multiple regression analysis is reasonable both in theory and in practice. The obtained empirical formula determining a is feasible and contributes to accuracy of computing sediment settling velocity, meeting the demand of design.