福建兴化湾海上风电场海底浅层结构及悬沙特征和沉积物输运分析研究

Research on the Shallow Structure and Suspended Sediment Characteristics and Sediment Transport Analysis of the Xinghua Bay Offshore Wind Farm in Fujian Province

海上风电工程设计对海底表层结构及沉积物输运特征的研究提出了更高的要求。本文针对福建兴化湾海域浅地层结构及水体悬沙和海底表层沉积物输运特征进行了系统地研究,并根据经验公式进行了计算。研究发现研究区内整体上表层沉积物类型大致围绕岛屿呈不规则环带状分布,沉积物颗粒较粗,大部分海域沉积物分选较差,与现今动力环境吻合;研究海域悬沙的中值粒径主要分布在0.003mm到0.539mm之间,平均中值粒径为0.122mm;研究海域岛屿周边近岸受到潮流波浪作用的影响。岛屿水道内沉积物分布由水道内横向环流和涨落潮流共同控制。海洋环流作用下的区域沉积物输运模式控制了研究区沉积作用的整体特征;此外,研究区位于闽浙沿岸泥质区的末端,受闽浙沿岸流的影响,沉积物输运过程有明显的季节性差异,夏季沉积物由南向北输运,向海输运较弱;冬季从北向南输运沉积物,但沿岸流的搬运能力在研究区减弱。冬季沉积物可以穿过剪切锋运向外海输送。这一模式导致研究区在高海平面时期沉积物供应来源虽复杂,但沉积的总量相对较少,因此形成的沉积层相对较薄。

The design of offshore wind power engineering has put forward higher requirements for the study of the surface structure and sediment transport characteristics of the seabed.This article systematically studies the shallow layer structure,suspended sediment transport characteristics,and surface sediment transport characteristics in the Xinghua Bay area of Fujian Province,and calculates them based on empirical formulas.The study found that the overall surface sediment types in the study area are roughly distributed in an irregular ring shape around the islands,with coarse sediment particles.Most of the sediment in the sea area is poorly sorted,which is consistent with the current dynamic environment;The median particle size of suspended sediment in the study area is mainly distributed between 0.003 mm and 0.539 mm,with an average median particle size of 0.122 mm;Study the impact of tidal waves on the nearshore areas around islands in the sea area.The distribution of sediment in island waterways is jointly controlled by lateral circulation and fluctuating currents within the waterways.The regional sediment transport model under the influence of ocean circulation controls the overall characteristics of sedimentation in the study area;In addition,the research area is located at the end of the muddy area along the Fujian Zhejiang coast.Due to the influence of the Fujian Zhejiang coastal currents,there are significant seasonal differences in sediment transport processes.In summer,sediment transport is weak from south to north,and to the sea;In winter,sediment is transported from north to south,but the transport capacity of coastal currents is weakened in the study area.In winter,sediments can be transported to the open sea through shear fronts.This model leads to the complex sediment supply sources in the study area during the high sea level period,but the total amount of sediment is relatively small,so the sedimentary layer formed is relatively thin.