小浪底水库运用后黄河下游河床调整规律

发布时间：2018-07-03 13:23

本文选题：河床调整 + 断面形态　；参考：《人民黄河》2016年10期

【摘要】：小浪底水库的运用改变了坝下游的水沙条件,引起了黄河下游河道的再造床过程,给防洪及滩地利用等带来了一系列影响。利用黄河下游1999—2015年水沙及断面地形等实测资料,分析了近期黄河下游河床的调整过程及特点:1进入下游河道的年均沙量仅为0.88亿t,累计河床冲刷量达18.7亿m3,其中游荡段冲刷量占总冲刷量的72%,在冲刷过程中河道纵比降变化不大,河床粗化较为明显,床沙中值粒径由建库前的0.06 mm增大到水库运用后的0.15 mm;2河床断面形态调整较为显著,下游各河段调整均表现为向窄深方向发展,其中游荡段主槽展宽较为明显,平滩河宽由1999年的943 m增大到2015年的1 275 m,过渡段及弯曲段的平滩河宽调整较小,此外各河段平滩流量也显著增大,游荡段、过渡段、弯曲段平滩流量分别由1999年汛后的3 229、2 339、3 080 m3/s增大到2015年汛后的7 126、4 864、4 721m3/s;3河床平面形态总体保持稳定,各河段深泓摆动幅度均有所下降,其中游荡段的年平均深泓摆动幅度由建库前的234 m降低到水库运用后的123 m;4河段尺度的平滩河槽形态参数(如平滩河宽、平滩水深、平滩面积、平滩流量)及深泓摆动强度与水库运用后前4 a平均的水流冲刷强度密切相关。
[Abstract]:The application of Xiaolangdi Reservoir has changed the conditions of water and sediment in the lower reaches of the dam, caused the process of reconstructing bed in the lower Yellow River, and brought a series of influences to flood control and beach utilization. Based on the measured data of water and sediment and section topography in the lower reaches of the Yellow River from 1999 to 2015, This paper analyses the recent adjustment process and characteristics of riverbed in the lower reaches of the Yellow River. The average annual sediment flow into the lower Yellow River is only 88 million tons, and the accumulated bed scour amount is 1.87 billion m3. The scour volume of wandering section accounts for 72% of the total scour volume. In the course of scouring, the river course is in the course of erosion. The longitudinal ratio drop does not change much. The mean diameter of bed sediment increased from 0.06 mm before the reservoir construction to 0.15 mm / 2 river bed profile after reservoir operation, and the adjustment of the lower reaches of the river showed a narrow and deep direction, and the river bed coarsening was obvious, and the average diameter of the bed sediment increased from 0.06 mm before the reservoir was built to 0.15 mm / 2 after the reservoir was put into operation. The width of the main channel in the wandering section increased from 943 m in 1999 to 1 275 m in 2015, and the width of the transitional section and the bend section of the section was adjusted slightly. In addition, the flat-beach discharge of each section also increased significantly, and the wandering section and the transitional section also increased significantly. The flat discharge in the bend section increased from 3 229 2 339U 3 080 m3 / s after the flood in 1999 to 7 126 4 864 4 721 m3 / s after the flood in 2015. The horizontal shape of the riverbed remained stable in general, and the amplitude of the deep swinging decreased in each reach. The annual average amplitude of deep swinging in wandering section is reduced from 234 m before reservoir construction to 123mt4 reach after reservoir operation. The shape parameters of flat channel (such as the width of flat river, the depth of flat bank, the area of flat beach) are reduced. The flat-beach discharge) and the intensity of deep swinging are closely related to the average scour intensity of the water flow in the first 4 years after the reservoir is put into operation.
【作者单位】：武汉大学水资源与水电工程科学国家重点实验室;
【分类号】：TV147

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