| 摘要: |
| 毛里塔尼亚友谊港所处海域为典型沙质海岸，面向大西洋，波浪作用下自北向南的沿岸输沙是其主要泥沙运动方式。该海岸泥沙中值粒径0.25 mm，年平均输沙约100 万m3。因为港口建设拦截了沿岸输沙，原本平直海岸线形成了港口北侧淤积和南侧冲刷的岸线形态。为保护堆场免受侵蚀，港口南侧于1991年建成了南挑丁坝，至2009年其南侧岸线已后退至根部，再度危及堆场和陆地设施安全。根据实测岸线资料，采用一线理论岸线演变数学模型，对港口南侧海岸不同防护方案进行了计算。结果显示，现有南挑丁坝与其南侧续建的T型丁坝之间岸线能很快调整至稳定状态，可对该岸段陆地设施起到保护作用。在现有丁坝南侧2 000 m处新建T型丁坝，平行于岸线的横头部分置于-2 m等深线，作为港口南侧岸线防护的推荐方案。沿岸输沙未得到补给的情况下，新的岸线防护工程在稳定上游岸线的同时，下游岸线的冲刷后退不可避免。考虑较长期限和更大范围的岸线稳定，还需采取每隔一定年限新建防护工程的措施。 |
| 关键词: 沿岸输沙 岸线演变 岸线防护 一线模型 友谊港 |
| DOI： |
| 分类号:TV148 |
| 基金项目: |
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| Coastline evolution and erosion control works at Friendship port in Mauritania |
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SUN Bo1,2, WANG Xiu-zhong3, SUN Lin-yun1,4
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1.Nanjing Hydraulic Research Institute, Nanjing;2.College of Harbor, Coastal and Offshore Engineering, Hohai University, Nanjing;3.CCCC First Harbor Consultants Co., Ltd., Tianjin;4.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing
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| Abstract: |
| The Friendship port (port of Nouakchott) in Mauritania is located on the east coast of the Atlantic Ocean, a typical sandy beach having mean sediment diameter 0.25 mm. Tidal currents are weak, while strong longshore transport from the north to the south induced by wave actions plays a main role in sediment movement. Previous studies show that the annual longshore sediment transport was about one million cubic meters. The construction of the port intercepted longshore sediment transport, which caused serious upstream accretion and downstream erosion and changed the original straight coastline. To protect the yard from erosion, a groin on the south side of the port was built in 1991. The erosion reached the end of the groin in 2009, and endangered once again the safety of the yard and other land facilities. According to the measured shoreline data, a “one-line theory” mathematical model was used to calculate shoreline evolutions for different protection schemes of the south coastline. T-shape groin was planned to build in the shore, where the transverse part can keep upstream sediment and prevented the head of the groin from wave attacks. The transverse part was 300 m long and was put along -2 m contour. Numerical modelling results show that the coastline between the new T-shape groin and the existing groin was soon adjusted to steady state and was fixed in position. The recommendation scheme for the south coastline prevention was to build a new T-shape groin 2 000 m downstream of the existing groin, which was implanted by the port authority in 2013. Due to strong longshore sediment transport, the new shoreline protection works fix upstream shoreline, while their downstream shoreline erosion is inevitable. Taking a longer duration and a greater range of shoreline stability into concern, new protection measures are needed every certain number of years. |
| Key words: longshore transport erosion control one line model Friendship port |
