摘要:
依托秦皇岛北戴河中海滩养护工程,对养滩前后不同时期抛沙区内外表层沉积物样品进行粒度实验,获得沉积物粒度参数,并结合Gao-Collins粒径趋势模型,对海滩养护后沉积物粒度变化特征、沉积物输运变化以及抛沙区外未养护海滩沉积物的影响进行研究。结果显示,海滩养护后,抛沙区内沉积物粒度总体细化,在养滩初到养滩之后6个月期间,抛沙区内沉积物变细、分选变好,这是由于外来抛沙的混杂和夏季ES向波浪的搬运作用,抛沙物质和原始海滩沙混合,抛沙区外变化趋势相反。养滩9个月后,由于冬季暴风浪的增多,抛沙区内沉积物遭受侵蚀并在抛沙区外淤积,抛沙区内沉积物变粗、分选变差,抛沙区外沉积物变细、分选变好。15个月后,抛沙区内外沉积物均变细,冬季侵蚀的海滩得到恢复。沉积物净运移趋势由沿岸输移逐渐变为垂岸输移,这是由于经过1年多的时间,海滩与区域动力环境相适应,海滩处于横向输沙动态平衡的状态,即夏季向岸输沙、冬季离岸输沙。
Abstract:
The data of this article are from the beach nourishment project in Beidaihe of Qinhuangdao. Surface samples were collected in different periods for dry sieving analysis. Changes in sediment grain size distribution pattern and their influence on a nourished beach were studied with grain size parameters as a main tool combining with Gao-Collins grain size trend analysis. Results showed that after sixth months of beach nourishment, the new beach sediments became finer and better sorted, due to the influence of nourishment and the southeast summer wave as well as the mixing of nourishing materials with the original beach sediments. In contrast, the trend of grain size variation was opposite beyond the nourished zone. As a result of the increase in winter storm wave, the nourished zone was eroded and beach sediments became coarser and worse sorted after ninth months of nourishment. After fifteen months of nourishment, however, beach sediments became finer again and the eroded beach was recovered to some extent. The net sediment transportation was then perpendicular to the coast instead of the alongshore transport. The beach reached a balanced status after one year of nourishment.
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