【作者】 刘蔡胤；

【导师】 张宁川；

【作者基本信息】 大连理工大学 ， 港口、海岸近海工程， 2008， 硕士

【摘要】 淤泥质港口和海岸泥沙问题研究是海岸动力学研究的重要组成部分。尽管所见文献众多,但可供实际工程规划、设计直接应用的成果甚少。诸如工程规划阶段对整体水域泥沙淤积量的估算方法、工程设计阶段对海底地形变化的判定方法、工程使用阶段对未来泥沙演变规律的预测方法等均无定论。该问题也是学术界多年来的热点研究问题和力争突破的方向之一。本文基于MIKE21软件,建立了包括杭州湾及长江口的大尺度的二维水动力学模型及港区水域小尺度粘性泥沙输移模型。利用同步实测资料对模型进行潮位、潮流及含沙量等的验证。验证表明本文建立的模型较好地再现了洋山深水港区水域水流运动特征,总体上可以正确地反映上海洋山深水港区水域水动力特征和泥沙运动规律。利用该模型对比计算研究了上海洋山深水港区将军帽—大指头汊道封堵前、后,整个港区水域海底地形演化过程,重点探讨了洋山港局部强淤原因,为洋山港下一步规划方案的选择提出了具体的建议。主要结论如下:(1)颗珠山汊道最终是否封堵不会根本上改变-30m水深以下峡道水域地形特征及现有水流特征,受影响范围相对局限于峡道西段开阔水域。(2)潮流场数学模型计算表明:封堵将军帽—大指头汊道水域后,封堵汊道工程前后水动力对比结果表明,工程前原有涨落潮相对涨潮微弱优势的单一状态被打破,港区南部海域落潮转为优势,而且优势明显,北部原有的涨潮优势进一步得到提高。(3)从两个方案实施后由潮量计算结果以及颗珠山汊道地形剖面为冲刷趋势,颗珠山汊道的存在对保持西港区现有的弱冲刷趋势非常有利。(4)大通道方案会在现有基础上继续加大落潮动力,而涨潮动力增加弱于落潮动力,也就是现有淤积水域会进一步淤进。(5)淤积范围还会往东走多远。从地形剖面分析结果-30m以下水深岸坡依然呈现弱侵蚀或相对平衡状态来看,淤积范围会保持现有区域内,不会再强势向东淤进。但是各剖面顶坡段、前坡段特别是项坡段淤积深度在现有的基础上会继续加大。(6)对于中部淤积带的成因及演变趋势,本文与天科所分析得到的结论不同;对于南部淤积带的成因及演变趋势,本文与天科所分析得到的结论比较,可以发现两者的观点基本一致。(7)从泥沙淤积角度建议保留颗珠山汊道。更多还原

【Abstract】 The transport of cohesive sediment based on the flow conditions was an essential part of Coastal Hydrodynamics. In systematic review, we are lacking of the achievement which can apply to project planning and design directly. In the period of project planning, we can’t find the general conclusion which can be applied to calculate the amount of silt deposit in the whole sea region . in the second period of design and project construction , we can’t estimate or calculate topographical change and in advance. Sediment problems have become an important issue and received extensive attention of scholars.We use the DHI MIKE21 model to study the hydrodynamics and sediment transport in the Yangshan port. First, a hydrodynamic model with the larger computational domain covering Hangzhou Bay and the Changjiang River Estuary was constructed to study the general characteristics of hydrodynamics and provide the hydrodynamic information as the boundary conditions in the following modeling of sediment transport with the smarter mesh sizes in the Yangshan port. Second, the models were validated by measurements, computed tidal level and current are in good accordance with the measured data. The computed suspended sediment concentration at different locations are also matched the field data generally. In sum, the characteristics of hydrodynamics and sediment transport in the Yangshan port are studied briefly based on the modeling results. The primary conclusions:(1) Blanking off the Kezhushan inlet won’t conduce to terrain change and flow field change severely in the region under 30m water depth .(2) By comparing the post-reclamation current fields with the pre-reclamation ones, we detected differences that the single state of flood tide dominated the field has been changed. The result further indicates that in the south port the ebb tide began to dominate the field strongly and in the north port the flood tide rised further.(3) Based on the contrast of computation tidal flow capacity and the eroding tendency in the Kezhushan inlet, the existence of the inlet can help to keep the current eroding tendency.(4) We used the valid model to analyze the project plan of separating region and whole region . The whole region plan will help to increase the dynamic of ebb tide and contribute to silting in the silted region. (5) How far will the silted region goes? From the analysis of coastal profiles under the 30m water depth, the silted region will remain steady. But the some specified silted district will aggravate the silting condition.(6) This dissertation meets Tiankesuo’s consequences in the cause of formation of silting areas in the south of port and finds some differences with the consequences in the middle of port.(7) In terms of sediment accumulation ,we suggest to keep the Kezhushan inlet.更多还原