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Methodology for Controlling Beach Erosion by Large Coastal Structures and Its Application

大型海岸结构侵蚀海滩控制方法及其应用

基本信息

批准号：
01850121
负责人：
TSUCHIYA Yoshito
金额：
$ 5.76万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01850121/
关键词：
Beach erosion Erosion control Beach change Beach stabilization Headland Methodology for erosion control Ogata coast

项目摘要

Based on the mechanism of beach erosion by a large coastal structure, a methodology for beach erosion control has been developed, and its applicability has also been investigated. The main results can be summarized as :1. Beach erosion by a large coastal structure is due to 1) impediment of longshore sediment transport by the structure, 2) formation of nearshore, circulation by changing wave field by the structure, and 3) reflected waves by sea walls and dikes. The mechanism of beach erosion was clearly shown by numerical simulations of shoreline change and nearshore circulation. Based on the mechanism a methodology for beach erosion control by headlands was proposed in relation to the formation of stable sandy beaches.2. Proposed are 1) a 3D model for sea bottom topography change prediction based on the coupled system of the governing equations of wair transformation, nearshore currents and bottom topography change, and 2) a long-term shoreline change prediction model by introducing the sorting phenomena of bottom sediment and horizontal mixing coefficients in surf zones. By the 3D model, sea bottom topography changes were shown in the formation process of stable sandy beach. By the long-term model, changes of shoreline and sediment properties in beach erosion were numerically predicted. By use of the numerical simulations, the applicability of the proposed methodology was discussed.3. An application of the methodology was made to Ogata coast. Construction of a headland has been being made. Sea bottom topography change by constructing a headland was observed, and predicted by the proposed models. Additionally, beach erosion in the reduction process of river deltas was investigated to find the applicability of the methodology for beach erosion control.It was concluded from these results that the proposed methodology for beach erosion control by headlands is applicable to stabilize the sandy beaches being eroded by large coastal structures.

基于大型海岸结构对海滩侵蚀的机理，提出了一种海滩侵蚀控制方法，并对其适用性进行了研究。主要结果如下：1.海岸大型构造物对海滩的侵蚀主要是由于构造物对沿岸泥沙输移的阻碍，2)近岸的形成，通过构造物改变波场形成环流，以及3)海堤和海堤的反射波。通过对岸线变化和近岸环流的数值模拟，清楚地揭示了海滩侵蚀的机理。在此基础上，针对稳定沙质海滩的形成，提出了利用滩地控制滩涂侵蚀的方法。提出了基于WAIR变换、近岸水流和海底地形变化控制方程耦合的三维海底地形变化预报模型，以及引入底泥分选现象和海浪带水平混合系数的长期岸线变化预报模型。通过三维模型，展示了稳定沙质海滩形成过程中海底地形的变化。利用该长期模型，对滩涂侵蚀过程中岸线和泥沙性质的变化进行了数值预报。通过数值模拟，讨论了该方法的适用性。并以绪方海岸为例进行了应用。海角的建设一直在进行中。利用所提出的模型，观测了通过建造海角而产生的海底地形变化，并对其进行了预测。此外，还对河流三角洲消减过程中的滩涂侵蚀进行了研究，探讨了该方法在滩涂侵蚀控制中的适用性，结果表明，本文提出的滩涂侵蚀控制方法适用于大型海岸建筑物侵蚀的沙质滩涂的稳定。