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本文主要研究悬移质级配与分组含沙量测量误差的修正问题。首先由指数流速分布公式以及相应的悬移质含沙量沿垂线分布公式,导出级配沿垂线分布公式,并在图2中用野外观测资料对此式进行了验证。然后对五点法、三点法、单点法以及定比混合法的级配测量误差进行了分析和比较,同时给出了各种测法的误差修正系数α_n的计算式。由此式进一步讨论了各种实测垂线平均级配的统一问题。最后对分组含沙量的修正方法进行了探讨。研究表明,泥沙粗细、测点数目以及布点方式对测量误差均有重要影响,不管那种取样方法,粗沙测量误差均大于细沙。本文认为,按照观测河段的水、沙条件来确定测点的数目和布点方法,是获得可靠测量成果所必须考虑的问题。
This paper mainly studies the correction of suspended sediment gradation and the measurement error of sub-group sediment concentration. First, the distribution formula of vertical distribution of gradation is derived from the index flow velocity distribution formula and the corresponding suspended sediment concentration along the vertical distribution formula, and the formula is verified by field observation data in Figure 2. Then the grading error of five point method, three point method, single point method and fixed ratio mixed method are analyzed and compared. At the same time, the calculation formulas of error correction coefficient α_n for various methods are given. By this formula, we further discuss the uniform problem of the average grading of various measured vertical lines. Finally, the method of correcting sediment concentration is discussed. The results show that the thickness of sediment, the number of measuring points and the way of arranging have an important influence on the measurement error. No matter what kind of sampling method, the measurement error of coarse sand is larger than that of fine sand. This paper argues that determining the number and location of measuring points according to the conditions of water and sand in the observation channel is a problem that must be considered in order to obtain reliable measurement results.