冬季波浪与人工岛联合作用下日月湾海滩冲淤演变特征

Evolution characteristics of beach erosion and accretion at the Riyue Bay under the combined impacts of winter waves and artificial island

人工岛作为一种新兴的海岸工程,它的建设所引起的岸滩冲淤和防护问题日益受到人们的关注。本文以海南万宁市日月湾人工岛为例,通过4期实测海滩剖面数据和多时相遥感影像,分析了冬季波浪与人工岛联合作用对日月湾海滩冲淤变化的影响,并结合海区波况,探究了海滩冲淤变化机理。研究表明,日月湾海区冬半年的平均有效波高与波浪周期明显强于夏半年,且波浪强度整体上呈现逐年上升的趋势,但在人工岛建设前后变化幅度较小;人工岛建设对海滩地貌变化有强烈影响,海滩呈现出岛后淤积而两侧侵蚀的显著特征,岛影区海滩不断淤积,岸线向海淤进达200m,甚至可能与人工岛相连形成连岛沙坝,人工岛后两侧海滩侵蚀,岸线向陆一侧蚀退最大距离达50m;海滩在冬季波浪和人工岛共同影响下,岸滩自北向南依次表现为稳定、侵蚀、淤积、相对稳定、略有侵蚀或淤积、侵蚀、淤积的冲淤变化特征。

As a new form of coastal engineering,the artificial island has been receiving increasing attentions from community to the beach erosion and accretion due to its construction.Based on the multi-temporal remote sensing images and four field surveys,the influence of winter waves combined with artificial islands on the erosion and accretion of the Riyue Bay beach has been analyzed.Besides,the mechanism of beach erosion and accretion was explored using the wave data in the adjacent sea area.Our new results show that the average significant wave heights and wave periods in the winter were obviously stronger than those in the summer,and the wave force generally shows an increasing trend year by year,but its variation is not significant around the artificial island before and after the construction of islands.The construction of artificial island has a significant impact on the beach topographic profile, showing the obvious characteristics of accretion in the area sheltered by the artificial island and erosion on two sides of the beach. The beach accreted continuously in the island shadow area, and theshoreline in that area moved up to 200 m towards the sea, which may even be linked with the artificial islands to form a tombolo. The beach was eroded and the maximum erosion distance of shoreline to land is about 50 m on both sides behind the artificial island. The Riyue Bay beach is strongly affected by the winter waves and artificial islands. From north to south, the beach was at a state of stability-erosion-accretion, relative stability, slight erosion or accretion-erosion-accretion.