输沙量法与断面法差别原因及其适用性研究——以三峡水库为例

Difference between Sediment-transport Balance and Topographic Change Methods and Applicability Research in the Three Gorges Reservoir

输沙量法和断面法是计算河道冲淤量变化和分析河床演变的两种常用方法。简单介绍了两种方法的计算模式,并根据输沙量法与断面法的特点,通过采用误差传播理论推导,对输沙量法和断面法的误差来源进行了研究,最后以三峡水库为例,在采用两种方法对三峡水库蓄水运用以来库区泥沙冲淤量进行了计算对比的基础上,对断面法与输沙率法的适应性进行了研究。结果表明:在三峡水库蓄水运用期间,因为水库的拦沙作用,库区河床的淤积率较高,采用输沙量法和断面法计算冲淤量时均较为可靠,相对而言,采用断面法可以较为灵活地计算三峡库区冲淤量的沿程分布,输沙量法则能够较好地反映库区不同粒径级泥沙的冲淤特性,两种计算方法的结合使用则能更为全面地分析研究三峡库区的泥沙冲淤分布及组成。此外,若具备更为丰富的泥沙干容重实测资料,输沙量法与断面法计算结果应基本一致。

Sediment-transport balance and topographic change methods are commonly used for the river bed erosion or deposition and river channel process.In this paper,the calculation mode of the two methods was introduced,and according to its character,the error propagation derivation method was applied,and the error source was researched,finally,with the Three Gorges Reservoir as the calculation example,based on the calculation conclusion and analysis,the applicability of the two methods was researched.The conclusion indicates that during the impoundment of the Three Gorges Reservoir,for large amount of the sediment is blocked in the reservoir,the sediment deposition ratio of the river bed in the reservoir is high,and they are both credible to calculate the sediment deposition with the two methods,and the two methods also have their own merits,the topographic change method can calculate the sediment erosion or deposition distribution along the reach easily,and the sediment-transport balance method can calculate the sediment erosion or deposition character of different grid size,and with the combination of the two methods can analysis the sediment erosion or deposition more comprehensively.Furthermore,if there are very abundant sediment dry density data,the calculation conclusion of the two methods can be in coincident.