| 摘要: |
| 实施人工岬角和海滩养护的软硬措施相结合的方法是探索解决海滩侵蚀问题的新举措之一。基于验证良好的水动力模型建立了泥沙输运和海床演变模型,对秦皇岛市新开河口至南山岸线海滩经整治修复工程实施后的泥沙输运和海床演变规律进行模拟分析。结果表明:大潮与常浪耦合作用下,研究区域周围海域流速整体上落急时刻大于涨急时刻,沙坝掩护水域的流速较弱,波浪在沙坝处增强并在沙坝后破碎并减弱;在沙坝处出现高悬沙浓度区域,悬沙浓度分布主要由底床切应力控制,部分受水动力影响。大潮与强浪耦合作用下,在沙坝处出现远大于常浪时的增强水流(波生流),方向与强浪向一致,波浪在沙坝处已破碎且沙坝对强浪的削减效率大于常浪;与常浪作用下不同,悬沙浓度场在强浪作用下沙坝处没有出现明显的高浓度区域。波流耦合作用下,人工岬角单独存在时护岸效果有限,工程实施后在人工岬角和人工沙坝的配合下,沙坝处侵蚀而沙坝后侧掩护区域淤积,沙坝起到了有效养护海滩的作用。 |
| 关键词: 人工岬角 海滩养护 波流耦合 泥沙输运 海床演变 |
| DOI：10.11693/hyhz20211200345 |
| 分类号:P753 |
| 基金项目:国家自然科学基金资助项目,41776098号,41976159号。 |
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| SEDIMENT TRANSPORT AND SEABED EVOLUTION UNDER ARTIFICIAL HEADLAND AND BEACH NOURISHMENT ENGINEERING |
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HAN Xue-Jian1, KUANG Cui-Ping1, GONG Li-Xin2, LI Wen-Bin1
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1.College of Civil Engineering, Tongji University, Shanghai 200092, China;2.The Eighth Geological Brigade, Hebei Geological Prospecting Bureau, Qinhuangdao 066000, China
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| Abstract: |
| It is a new measure to solve beach erosion issue by combing hard and soft methods, e.g. artificial headland and beach nourishment. Based on a well-validated hydrodynamic model, a numerical model of sediment transport and seabed evolution was established to simulate the sediment transport and seabed evolution of the beach between the Xinkai estuary and Nanshan in Qinhuangdao in a beach renovation and restoration engineering project. Results indicate that under the combined action of spring tides and normal waves, the speed of current at the maximum ebb is generally larger than that at the maximum flood. The speed of current within the shielded area behind sandbars is low. Meanwhile, the waves are enhanced on sandbars and broken behind them and thus weakened. The high concentration of suspended sediment appears on the sandbars. The distribution of suspended sediment concentration is mainly determined by the bed shear stress and partly influenced by the hydrodynamics. Under the combined action of spring tides and strong waves, the enhanced currents, i.e. wave-induced currents in the same direction of strong waves, occurs on the sandbars. The strong waves are broken atop the sandbars, which attenuate the strong waves more efficiently than the normal waves. Unlike the normal wave condition, the high suspended sediment concentration area does not appear at the sandbars under strong wave condition. Under the current-wave coupling, the protection effect of sole artificial headlands is not prominent. However, with the combined cooperation of artificial headlands and sandbars, the sandbars are effectively protected and the beach is nourished by sacrificing themselves to enrich the shielded areas. |
| Key words: artificial headland beach nourishment current-wave coupling sediment transport seabed evolution |
