南海北部海底沙波演化特征的数值研究
发布时间：2019-07-04 13:55
【摘要】：南海北部外陆架地质构造、地貌类型和海底水动力条件均比较复杂，发育有大量海底沙波地貌，，是威胁海底工程设施安全的重要因素之一。多数情况下，沙波是一种具有活动性的海底地貌，在潮流、暴风浪流或内波等的作用下会产生快速迁移，沙波的迁移可能造成海底管道的悬空或掩埋，严重的可能会造成海底输油管道的断裂、钻井平台的倾斜垮塌、航道淤积、海底光缆的断裂等重大危害。虽然前人曾在该区域对海底沙波做过一些工作，但仍有许多科学问题有待深入研究。 本文在南海北部海底沙波已有研究的基础上，选取重点研究区对海底沙波的演化特征进行运算分析。总结分析了研究区表层沉积物以及沙波的特征；利用ROMS模型模拟了研究区2010年至2011年的底部流场数据；计算了研究区特定站位的泥沙起动流速；利用Rubin公式和筱原-椿东一郎公式模拟计算了沙波的迁移规律，并与搜集所得资料进行对比分析；结合台风资料以及底流数据，分析台风对海底沙波运移的影响。获得的主要认识如下： 南海北部沙波区Ⅰ和Ⅱ的表层沉积物可分为砂质砾、砾质砂、砾质泥质砂、含砾砂共4种类型，该区域表层沉积物中值粒径在0.233-2.234mm之间，均值为1.414mm；发育有脊线走向为NE-SW的直线型沙波，陡坡倾向主要为NW和SE，波高0.5m以下的沙波分布广泛，最大为5.67m。研究区沙波在2010年至2011年间有向南向东方向移动的趋势。 结合底流资料，使用Rubin公式对研究区内海底沙波运移方向的计算结果和搜集所得资料比较吻合，均为向东向南方向；不同站点的迁移距离在0-21.8m之间。应用筱原-椿东一郎公式对某站位运移距离的数值计算结果为0.25m，计算结果较Rubin公式的1.9m明显偏小。 “凡亚比”超强台风显著增强了研究区内的底流流速，增幅可达25-35cm/s。研究区内两个点位在“凡亚比”台风影响期间的迁移距离计算结果为2.0m、2.9m，分别占其年运移量的9.17%和26.36%，说明台风过境对海底沙波产生重大的影响。
文内图片：
图片说明：水下沙波形成机理示意图
[Abstract]:The geological structure, geomorphological types and hydrodynamic conditions of the outer shelf in the northern South China Sea are complex, and a large number of seafloor sand wave landforms are developed, which is one of the important factors threatening the safety of seafloor engineering facilities. In most cases, sand wave is a kind of active seafloor geomorphology, which will migrate rapidly under the action of tidal current, storm wave current or internal wave. The migration of sand wave may cause the suspension or burying of submarine pipeline, which may cause the fracture of submarine oil pipeline, the tilt collapse of drilling platform, the siltation of waterway, the fracture of submarine optical cable and so on. Although some work has been done on seafloor sand waves in this area, there are still many scientific problems to be studied in depth. Based on the existing research of seafloor sand waves in the northern South China Sea, this paper selects the key study areas to analyze the evolution characteristics of seafloor sand waves. The characteristics of surface sediments and sand waves in the study area are summarized and analyzed, the bottom flow field data of the study area from 2010 to 2011 are simulated by ROMS model, the sediment starting velocity at specific stations in the study area is calculated, and the migration law of sand waves is simulated and calculated by using Rubin formula and Xiaoyuan-Chundong Ichiro formula, and the results are compared with the collected data. Based on typhoon data and bottom current data, the influence of typhoon on seafloor sand wave migration is analyzed. The main understandings obtained are as follows: the surface sediments of sand wave area 鈪
本文编号：2509963
文内图片：
图片说明：水下沙波形成机理示意图
[Abstract]:The geological structure, geomorphological types and hydrodynamic conditions of the outer shelf in the northern South China Sea are complex, and a large number of seafloor sand wave landforms are developed, which is one of the important factors threatening the safety of seafloor engineering facilities. In most cases, sand wave is a kind of active seafloor geomorphology, which will migrate rapidly under the action of tidal current, storm wave current or internal wave. The migration of sand wave may cause the suspension or burying of submarine pipeline, which may cause the fracture of submarine oil pipeline, the tilt collapse of drilling platform, the siltation of waterway, the fracture of submarine optical cable and so on. Although some work has been done on seafloor sand waves in this area, there are still many scientific problems to be studied in depth. Based on the existing research of seafloor sand waves in the northern South China Sea, this paper selects the key study areas to analyze the evolution characteristics of seafloor sand waves. The characteristics of surface sediments and sand waves in the study area are summarized and analyzed, the bottom flow field data of the study area from 2010 to 2011 are simulated by ROMS model, the sediment starting velocity at specific stations in the study area is calculated, and the migration law of sand waves is simulated and calculated by using Rubin formula and Xiaoyuan-Chundong Ichiro formula, and the results are compared with the collected data. Based on typhoon data and bottom current data, the influence of typhoon on seafloor sand wave migration is analyzed. The main understandings obtained are as follows: the surface sediments of sand wave area 鈪
本文编号：2509963
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