导堤型河口航道淤积方式及长江口深水航道回淤研究

发布时间：2018-03-04 11:03

本文选题：导堤型河口　切入点：淤积方式　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：河口区域是河流与海洋沟通的枢纽,且因资源丰富和交通便捷等优势,成为经济文化发达、对区域发展起重要作用的地带。受流域及沿海人类活动的剧烈影响,河口区域海岸环境面临重大变化,出现航道淤积等问题,严重制约着河口地区的可持续发展。目前,由于人工对河口区域的整治,逐步形成在导堤和丁坝等工程控制下的导堤型河口。为了研究此类河口航道淤积问题,为河口治理和航道维护提供技术支撑,本文从河段展宽、潮径顶托、河势不顺、局部环状水流和异重流潜入五个方面,探讨了导堤型河口航道的淤积方式,具体包括:(1)河段展宽淤积方式,即河段展宽导致流速及挟沙力减小诱发淤积;(2)潮径顶托淤积方式,即径流和潮流相互作用,形成滞流区造成泥沙淤积;(3)河势不顺淤积方式,即河口及导堤形成的流路中心线与水动力轴线夹角偏大,水流泥沙受阻淤积;(4)局部环状水流淤积方式,即河口丁坝工程导致坝间存在局部漩流、环流,在局部环状水流作用下泥沙进入航道造成淤积;(5)异重流潜入淤积方式,即坝间泥沙落淤,经过航道形成异重流,下潜归槽入航道形成淤积。此外,以中国主要河流为背景,建立概念性河口模型,通过计算模拟流场,分析阐述了各种淤积方式。在此基础上,文中建立了长江口深水航道数学模型,利用实测数据对模型的潮位、流速流向进行了验证。对应导堤型河口的五种淤积方式,分析了造成长江深水航道回淤的可能原因。
[Abstract]:Estuarine region is the hub of river and ocean communication, and because of the advantages of rich resources and convenient transportation, it has become an economic and cultural developed zone, which plays an important role in regional development. The coastal environment of estuarine region is faced with great changes, such as channel siltation and so on, which seriously restrict the sustainable development of estuarine area. At present, due to artificial regulation of estuarine area, In order to study the siltation of such estuary channel and provide technical support for estuarine regulation and channel maintenance, this paper broadens the river reach, supports the top of the tide path, and the river regime is not smooth, in order to study the siltation problem of this kind of estuarine channel, which is gradually formed under the control of projects such as guided-dike and spur dike, etc. In this paper, five aspects of local annular flow and gravity current infiltration are discussed, and the silting modes of the channel of estuarine type of guide embankment are discussed, including the widening siltation mode of the reach of the river, that is, the expansion of the reach leads to the velocity of flow and the reduction of sediment carrying capacity, which induces siltation at the top of the tidal path. In other words, the interaction between runoff and tidal current results in the formation of sediment deposition in stagnant area (3) the river regime is not in conformity with the sedimentation mode, that is, the angle between the central line of the flow road and the hydrodynamic axis formed by the estuarine and the guiding embankment is larger, and the flow and sediment are blocked and silted. That is, the estuarine dike project leads to the existence of local swirl flow between dams, circulation, and sediment entering the waterway under the action of local annular flow, causing siltation to sink into the siltation mode, that is, the silt between dams falls and forms a density current through the waterway. In addition, taking the main rivers in China as the background, a conceptual estuarine model is established. By calculating the simulated flow field, various deposition modes are analyzed. The mathematical model of the Yangtze Estuary deepwater channel is established, and the tidal level and velocity direction of the model are verified by the measured data. The possible causes of the desilting in the deep water channel of the Yangtze River are analyzed according to the five siltation modes of the river mouth.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U617

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