| 摘要: |
| 跨海大桥的建设有利于环湾经济的发展，但桥墩入水不可避免地会对海湾内水动力和水交换造成一定的影响。本文以胶州湾为例，利用无结构网格有限体积海洋模型，建立了能够描绘胶州湾跨海大桥入海桥墩的高精度网格，构造了胶州湾及邻近海域的三维水动力模型，模拟了胶州湾建桥前后的潮（余）流结构。在此基础上，通过污染物示踪对比了胶州湾内污染物在建桥前后的对流扩散过程。模拟结果表明，大桥的建设对胶州湾南部大部分区域的影响较小，包括潮（余）流、水交换等方面；但对大桥北侧以及南侧靠近大桥一定范围内的区域有显著影响。大桥北侧潮致余流整体减小约2cm/s，靠近桥南侧的余流则由向北转为沿桥向东流动。由于大桥的影响，污染物在大桥北侧堆积，重点集中于桥北的红岛以西（Ⅰ区）沿岸区域以及红岛以东（Ⅱ区）大部分区域。其中，Ⅰ区建桥后的半交换时间增加了2.00d，Ⅱ区增加了2.04d。在减缓污染物扩散速率的同时，大桥也同样阻碍了径流输出的淡水向胶州湾南部的输运，使得桥北水体的盐度降低，有可能是造成近年来胶州湾冬季冰情加剧的原因之一。 |
| 关键词: 胶州湾跨海大桥 潮致余流 水交换 污染物输运 数值模拟 |
| DOI：10.11693/hyhz20180900211 |
| 分类号:P731.26 |
| 基金项目:国家重点基础研究发展计划（973计划），2015CB452905号；国家自然科学基金委—山东联合基金，U1706215号。 |
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| IMPACT OF THE CROSS-BAY BRIDGE ON WATER EXCHANGE IN JIAOZHOU BAY, QINGDAO, CHINA |
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CHEN Yan-Yu1,2, SONG De-Hai1,3, BAO Xian-Wen1,2,3, YAN Yu-Han1,2
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1.Key Laboratory of Physical Oceanography, Ministry of Education, at Ocean University of China, Qingdao 266100, China;2.College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China;3.Pilot National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China
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| Abstract: |
| The construction of the cross-bay bridge in the Jiaozhou Bay (JZB) benefits the socioeconomic development of the bay. However, many piers would affect inevitably the hydrodynamic and water-exchange in the bay. We established a three-dimensional tidal model in high spatial resolution to quantify the impact based on an unstructured mesh and finite-volume community ocean model (FVCOM). We applied a passive-tracing module to find out the changes of pollutant transport in JZB. The results show that the tidal (residual) current and the water-exchange capacity after the bridge buildup were changed slightly in most of the southern bay but greatly in the northern side especially in the areas adjacent to the bridge. The residual current was reduced by about 2cm/s and the direction was shifted from northward to eastward along the bridge in the south. The piers obstructed contaminant from dispersion in the continental side of the bridge, namely, the west of Hongdao (SectionⅠ) and the east of Hongdao (SectionⅡ). The half-life time in SectionsⅠandⅡincreased by 2.00d and 2.04d, respectively, and the journey of river water to the sea became longer after the bridge construction, which has lowered the salinity in the north of the bridge, resulting probably in the aggravation of sea ice in winter in JZB. |
| Key words: Jiaozhou Bay Cross-bay Bridge tidal residual current water exchange contaminant transport numerical modeling |
