长江河口南北槽分流口工程及瑞丰沙地形变化对落潮分流比的影响研究

发布时间：2018-05-11 10:35

本文选题：分流比 + FVCOM　；参考：《华东师范大学》2017年硕士论文

【摘要】：长江口北槽落潮分流比在深水航道整治工程之后经历了大幅下降的过程,对于潮汐影响下的河口,落潮分流比是维系分汉河段主支汊道稳定的关键指标,因此对于北槽落潮分流比下降原因的研究引起了很多学者的关注。本文通过野外观测与数值模型相结合的方法来研究分流口工程及瑞丰沙地形变化对南北槽落潮分流比的影响。经过研究发现:2015年夏季断面走航观测显示涨落潮过程中南槽的水通量大于北槽,且水流流速越大南北槽水通量的差距就越大.,北槽大潮落潮分流比为41.9%,小潮落潮分流比为43.1%;小潮落潮分流比稍大于大潮落潮分流比。现有分流口潜堤工程对于稳定南北槽分流口的河势、稳固江亚南沙发挥了积极的作用,但是潜堤本身对于北槽落潮分流比的影响较小,而潜堤方向的变化则会有效的改变南北槽落潮分流比,其中潜堤向南偏转对南北槽落潮分流比的影响大于向北偏转;当潜堤角度发生变化时,南北槽上断面的落潮分流比变化比下断面的变化大,这是由于北槽上下断面之间的横沙通道的平衡作用所致。.近20年,瑞丰沙河段地形在人为挖沙等因素的影响之下发生了剧烈的变化该河段从原来的"W"型河槽转化为"U"型河槽,河槽深泓线向北转移,过水断面面积增加,大流速区域向北岸偏移;瑞丰沙挖沙以及对应的南港下段地形的调整有利于增加北槽上断面落潮分流比,但由于横沙通道的调节,对于北槽下断面的落潮分流比影响甚微。
[Abstract]:The falling tide distribution ratio of the northern channel of the Yangtze River Estuary has experienced a significant decline process after the regulation project of the deep water channel. For the estuaries under the influence of the tide, the drop tide distribution ratio is the key index to maintain the stability of the main branch of the Fan-Han River reach. Therefore, many scholars have paid close attention to the study of the reasons for the drop-tide ratio of the north channel. In this paper, the influence of the diversion project and the topography of Ruifengsha on the downtrend distribution ratio of the north and south trenches is studied by combining the field observation with the numerical model. The results show that the water flux in the south channel is larger than that in the north channel during the summer of 2015. The larger the flow velocity is, the greater the water flux difference between the north and south channels is. The ratio of the low tide to the lower tide is 41.9, the ratio of the low tide to the lower tide is 43.1, and the ratio of the low tide to the lower tide is a little larger than that of the big tide. The existing submersible dike works have played a positive role in stabilizing the river regime and stabilizing Nansha of the north and south channels, but the influence of the submersible dike itself on the downtrend distribution ratio of the north channel is relatively small. But the change of the direction of the submersible embankment will effectively change the down-tide diversion ratio of the north and south trenches, and the influence of the south deflection of the submersible embankment on the downtrend distribution ratio of the north and south trenches is greater than that on the north side, when the angle of the submersible embankment changes, The variation of the falling tide distributary ratio in the upper section of the north and south channel is greater than that in the lower section, which is due to the balance between the upper and lower sections of the north channel. In the past 20 years, the topography of the Ruifeng Shahe River section has undergone drastic changes under the influence of artificial dredging and other factors. The section has been transformed from the original "W" type channel to a "U" type channel, and the deep channel line has been transferred northward, and the cross section area has increased. The large velocity area is shifted to the north shore, the dredging sand of Ruifengsha and the adjustment of the topography of the lower section of Nangang are beneficial to increase the down-tide distributary ratio of the upper section of the northern channel, but due to the adjustment of the transverse sand passage, it has little effect on the down-tide distribution ratio of the section under the northern trough.
【学位授予单位】：华东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV148

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