长江口青草沙水库前沿河床演变与失稳风险研究

发布时间：2018-02-08 11:16

本文关键词： 河床演变青草沙水库长江口水库前沿分流口河槽冲刷　出处：《海洋工程》2017年02期 　论文类型：期刊论文

【摘要】：位于长江口南北港分流口的青草沙水库是上海市最大的城市供水水源地,开展该水库前沿河床稳定性和失稳风险研究具有重要的理论意义和工程指导价值。基于此,利用长江口南北港分流口2000年至2013年期间实测的高精度地形资料,分析青草沙水库前沿河床近期地貌变化特征,为水库库堤安全预警提供相关理论支撑。结果表明:青草沙水库前沿河床冲淤变化在建库前后有明显差异,建库前总体表现为河槽冲刷、沙洲淤积,呈现准冲-淤振荡的性质;建库后变为幅度逐渐减弱的持续冲刷;沿河床河槽形态由U型向U型与V型河槽叠加的复式河槽转变。青草沙水库前沿沙体沿落潮主流方向下移,成形沙体呈先增长、再减少,最后趋于平衡的态势,隐形沙体大体呈减少趋势。青草沙水库库堤前沿近600 m位置是河床失稳的重点风险区域,尤其是水库库堤中上部河床处于不稳定状态,如前沿边坡所在河槽进一步逼近水库前沿,则河床面临进一步冲刷的可能。
[Abstract]:Qingcaosha Reservoir, located at the diversion port of the Yangtze River Estuary, is the largest urban water supply source in Shanghai. It is of great theoretical significance and engineering guiding value to study the stability and instability risk of the riverbed in the front of the reservoir. Based on the high-precision topographic data measured from 2000 to 2013 at the diversion port of the Changjiang Estuary, the recent geomorphological characteristics of the riverbed in the front of Qingcaosha Reservoir are analyzed. The results show that there are obvious differences before and after construction of Qingcaosha Reservoir, and before and after the establishment of the reservoir, the overall performance of the reservoir is channel erosion, silt silt, showing the nature of quasi-scour and silt oscillation. After the reservoir was built, it became a continuous scour with decreasing amplitude, and the shape of channel along the river bed changed from U-type to double-channel superimposed by U-type and V-type channel. The sand body in the front of Qingcaosha Reservoir moved down along the main direction of falling tide, and the formed sand body increased first, then decreased. Finally, there is a tendency to balance the invisible sand body, and the nearly 600m position of the front of Qingcaosha reservoir embankment is the key risk area of riverbed instability, especially in the unstable state of the upper and middle part of the reservoir embankment. If the channel of the front slope is closer to the reservoir front, the riverbed may be scoured further.
【作者单位】：华东师范大学河口海岸学国家重点实验室;
【基金】：国家自然科学基金资助项目(41576087) 2015广西高等学校科学研究人文社科重点资助项目(KY2015ZD133)
【分类号】：TV147

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