淤泥质海岸深水航道回淤强度数值研究

发布时间：2018-07-04 07:54

本文选题：航道回淤 + 风　；参考：《中国海洋大学》2014年硕士论文

【摘要】：淤泥质海岸深水航道的泥沙淤积一直是困扰航道开挖和港口建设的突出问题，对航道回淤状况进行现场勘测也往往受海况、成本等因素制约，面临着许多现实的困难和挑战；而对淤泥质海岸深水航道回淤强度进行数值模拟研究，不仅会节省大量的成本，还可以针对极端海况下航道的回淤强度进行模拟预报，这对于类似海岸下航道选址和港口规划都具有重要的意义。本文基于靖海湾海域这一浪控和潮控的淤泥质复合型海湾，综合运用波浪、潮流、泥沙数学模型，从以下三个方面进行了数值研究: 首先，运用MIKE21SW谱波浪模型分别以2004、2005年的风场数据为驱动，针对中国连云港-韩国罗州群岛连线以北，中国威海成山头-朝鲜长山串连线以南的黄海海域大范围波浪进行模拟，并与实测值进行对比验证，验证结果良好。然后用MIKE21HD FM水动力模型、MIKE21MT FM粘性泥沙模型对靖海湾海域大潮和小潮期的潮流、泥沙进行了数值模拟，根据实测站位数据分别对潮位、流速、流向、悬沙浓度进行了对比验证，验证结果总体上比较良好。其次，对纯潮流作用下20万吨级航道的四季冲淤演变进行数值模拟，分析纯流作用对靖海湾海域海床高度变化的影响；重点对风、浪、流共同作用下10万吨级和20万吨级航道四季的底床冲淤演变、航道纵向不同研究剖面沿程淤积进行数值模拟分析，并对比了两种工况航道横向断面的年回淤强度和航道沿程年回淤强度；通过20万吨级航道在纯流作用和风、浪、流共同作用两种不同模拟情况的对比，分析靖海湾海域的冲淤以及航道沿程年回淤强度变化规律。研究结果表明：外航道3km-4km里程段是航道年淤积强度最高的位置；随着航道开挖水深的增加，航道沿程淤积高峰厚度和淤积范围都有所增大，随着航道向深海延伸，回淤强度逐渐减小；加入风、浪影响后，航道的回淤强度明显增强，这种影响在风、浪作用较强的夏季表现的尤为明显。最后，参考相关水文规范和以往研究成果，确定此区域50年一遇的12种极端海况潮位和波浪要素，对极端海况作用24小时后，，研究区域的悬沙分布、海床高度变化和航道回淤强度进行了预报分析。研究结果表明：短时间内因台风、寒潮等复杂海况形成强波浪和极端增水，增大了泥沙的掀扬和输移，使得航道淤积高峰位置向近港方向移动；极端海况加剧了深水航道在短时间内的回淤强度，其一天产生的淤积量相当于平时几倍甚至十几倍,工程中应引起足够的重视。
[Abstract]:Sediment deposition in deep water channel of muddy coast is always a prominent problem that puzzles channel excavation and port construction. Field survey of channel siltation is often restricted by sea conditions, cost and other factors, and it faces many practical difficulties and challenges. The numerical simulation study on the silt strength of the silt coast deepwater channel can not only save a lot of cost, but also predict the siltation intensity of the channel under extreme sea conditions. This is of great significance for similar coastal channel location and port planning. In this paper, based on the wave control and tidal control silt complex bay, the mathematical models of wave, tidal current and sediment are comprehensively used to study the following three aspects: first of all, Based on the wind field data of 2004 and 2005, the Mi KE21SW wave model is used to simulate the large range of waves in the Huang Hai sea area north of Lianyungang and Raozhou Islands in South Korea, south of the Chengshantou of Weihai in China and Changshan in Korea. The results are compared with the measured values and the results are good. Then, using the MIKE21HD FM hydrodynamic model and MIKE21MT FM viscous sediment model, the tidal current and sediment during the spring tide and the low tide in Jinghai Bay are numerically simulated, and the tidal level, velocity, flow direction and suspended sediment concentration are compared and verified according to the measured station data. The results are good on the whole. Secondly, the four seasons scour and siltation evolution of 200 000 ton waterway under pure tidal current is simulated, and the influence of pure current on sea bed height in Jinghai Bay is analyzed, with emphasis on wind and wave. Under the combined action of flow, the bottom bed scour and siltation evolution of 100,000-ton and 200,000 tonnage waterways are simulated and analyzed by numerical simulation. The annual siltation intensity and the annual siltation intensity along the channel are compared between the transverse section of the channel under two operating conditions, and the comparison of the two different simulation cases of the combined action of wind, wave and current in the pure current, wind, wave and current through the 200 000 ton waterway. The changes of erosion and siltation intensity along the channel are analyzed. The results show that the 3km-4km mileage of the outer waterway is the position with the highest annual siltation intensity of the channel, and with the increase of the depth of the channel excavation, the maximum thickness and the range of the siltation along the channel increase, and as the channel extends to the deep sea, The siltation intensity decreases gradually and the siltation intensity of the channel increases obviously after the addition of wind and wave, especially in the summer when wind and wave action are stronger. Finally, with reference to relevant hydrological norms and previous research results, the distribution of suspended sediment in the study area after 24 hours of action on extreme sea conditions is determined by determining the tidal level and wave elements of 12 extreme sea conditions that occur once in 50 years. The variation of sea bed height and the siltation intensity of channel are forecasted and analyzed. The results show that strong waves and extreme water increase due to typhoon, cold wave and other complex sea conditions in a short period of time, which increase the lift and transport of sediment, and make the channel siltation peak position move towards the port direction; The extreme sea condition intensifies the desilting intensity of deepwater channel in a short period of time, and the amount of siltation produced in one day is several times or even more than ten times as much as that of normal times, so enough attention should be paid to it in engineering.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U612.2

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