陈栋, 余明辉, 朱勇辉. 三峡建库前后下荆江有效流量研究[J]. 水科学进展, 2018, 29(6): 788-798. DOI: 10.14042/j.cnki.32.1309.2018.06.004
引用本文: 陈栋, 余明辉, 朱勇辉. 三峡建库前后下荆江有效流量研究[J]. 水科学进展, 2018, 29(6): 788-798. DOI: 10.14042/j.cnki.32.1309.2018.06.004
CHEN Dong, YU Minghui, ZHU Yonghui. Study on effective discharge in the Lower Jingjiang River before and after construction of the Three Gorges Dam[J]. Advances in Water Science, 2018, 29(6): 788-798. DOI: 10.14042/j.cnki.32.1309.2018.06.004
Citation: CHEN Dong, YU Minghui, ZHU Yonghui. Study on effective discharge in the Lower Jingjiang River before and after construction of the Three Gorges Dam[J]. Advances in Water Science, 2018, 29(6): 788-798. DOI: 10.14042/j.cnki.32.1309.2018.06.004

三峡建库前后下荆江有效流量研究

Study on effective discharge in the Lower Jingjiang River before and after construction of the Three Gorges Dam

  • 摘要: 有效流量是天然河流某一时段内悬移质输沙量最大所对应的流量,可反映中、短期造床作用。根据监利水文站1991—2016年逐月流量、输沙量及悬移质级配,分析三峡建库前后流量频率及不同粒径组悬移质泥沙输移特性;运用理论分析法与分组频率法计算下荆江分组悬移质输沙量对应有效流量的大小、重现期、历时。研究成果表明:受来水来沙、水流挟沙能力以及床沙补给等因素影响,有效流量随泥沙粒径增大而减小。建库后,因河床冲刷各粒径组间有效流量偏差增大,0.062 mm < d < 0.25 mm粒径组泥沙对应的有效流量增大,其他粒径泥沙和全部悬移质对应的有效流量减小;d<0.125 mm粒径组泥沙有效流量重现期增大,d>0.125 mm粒径组泥沙有效流量重现期减小;细颗粒泥沙含沙量严重不饱和河道输送粗颗粒泥沙的能力相对较大,悬移质级配粗化;累积50%的泥沙输移需43%~82%的累积流量以及62%~90%的累积历时,且累积流量和累积历时随着泥沙粒径的增大而减小和缩短。研究三峡建库前后有效流量变化对分析冲刷条件下下荆江河段河床演变具有重要意义。

     

    Abstract: Effective discharge is the flow rate corresponding to the maximum suspended sediment transport within a certain period of time in a natural river, which can reflect the medium to short term bed-forming effect. Flow frequency and features of suspended sediment transport of different particle size groups before and after the construction of the TGD are analyzed, based on the prototype data from 1991 to 2016 in the Jianli hydrological station of the mean monthly flow rate and suspended sediment discharge and the suspended sediment gradation. The magnitude, return period and duration of the effective discharge corresponding to the suspended sediment grouped transport in the Lower Jingjiang River are investigated via theoretical analysis and magnitude-frequency approach. The results showed that, as influenced by factors such as coming flow and sediment, sediment transport capacity and bed material replenishment, the effective discharge decreases with the increase of particle size. The deviation of effective discharge between various particle groups is increased after the construction of the TGD. The effective discharge corresponding to the particle group with 0.062 mm < d < 0.25 mm increases, and decreases for the other particle groups and for all suspended load after the construction of the TGD. The return period of the effective discharge corresponding to the particle group with d<0.125 mm increases, while decreases with d>0.125 mm. After the construction of the TGD, the cumulative discharge and cumulative duration of the cumulative transport of 50% sediment decreases with the increase of the particle size. Because of the severe unsaturation of fine sediment and relatively large transport capacity of coarse sediment, roughening of the suspended sediment gradation is resulted in. 50% of the cumulative sediment transport requires 43%—82% cumulative discharge and 62%—90% cumulative duration. Studying the changes in effective discharge before and after the construction of the Three Gorges Dam (TGD) is of significant importance to analyze the riverbed evolution in the Lower Jingjiang River under erosion conditions.

     

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