多工程和波流耦合作用下养护海滩的地貌演变特征

Morphological Evolution Characteristics of a Nourished Beach Under Multi-project Influence and Coupled Wave-current Interaction

摘要:

为探究秦皇岛市戴河口至洋河口岸段海滩在养护工程实施后的地貌演变特征，采用双重嵌套网格技术在验证良好的波流耦合水动力模型基础上建立该海域的泥沙输运及海床演变模型，模型得到了实测资料的良好验证。模型的计算结果及实测剖面资料表明：潮流和常浪耦合下的泥沙分布与潮流和和强浪耦合下的泥沙分布形式一致，平均泥沙浓度及工程前后泥沙浓度增加值落急时刻大于于涨急时刻；工程后沙坝周围出现悬沙高浓度带，常浪时位于沙坝向岸侧，强浪时带位于沙坝向海侧；工程后沙坝处发生侵蚀，沙坝向岸侧发生淤积，沙坝向岸移动，工程在有无风暴潮的情况下均能起到保护海滩的作用。

Abstract:

In order to investigate the morphological evolution characteristics of the nourished beach， the sediment transport and morphological model was applied and well verified against the measured data on the base of the well-validated wave-current coupled hydrodynamic model using the double nested grid technology. The model results and the measured beach profiles indicate some characteristics of the sediment concentration and the beach morphology： the sediment concentration distribution under the coupled tidal current and normal waves is consistent with that under the coupled tidal current and strong waves， and the averaged sediment concentration and the sediment concentration difference between post- and pre-engineering are larger at the maximum ebb than flood； in post-engineering scenario， the high sediment concentration area locates on the onshore side of the sandbars under the normal waves and on the offshore side under the strong waves； in post-engineering scenario， the erosion and deposition takes place at the sandbars and at the onshore area respectively， and the sandbars move onshore， which indicates that the nourishment project can protect the beach regardless of whether a storm surge occurs.