水动力对越南巴达棱湾表层沉积物和岸滩的影响

The influence of Hydrodynamics on surface sediment and beach in the Cu Lao Cau Bay,Vietnam

基于越南巴达棱湾2007年4月采集的42个表层沉积物样品及实测水文资料,分析越南巴达棱湾表层沉积物特征,并结合GSTA模型分析表层沉积物的运移趋势。结果表明:越南巴达棱湾表层沉积物以粗颗粒为主,在潮流和波浪的作用下呈中西部粗、东部细的分布特征;其西侧表层沉积物沿岸线自西南向湾内运移,中西近岸区沉积物垂直于岸线做离岸输移,在湾的东侧存在自东北向西南的运移趋势,并与从湾西运移过来的底沙相遇,形成运移辐聚区,并在余流的作用下,向西运移;"波浪掀沙,潮流输沙"是该地区表层沉积物输运的主要作用机制;在波浪的作用下,研究海域的海岸线处于侵蚀状态,有后退的趋势。

This study analyzed 42 surface sediment samples and hydrological data observed in Aprial, 2007 in the Cu Lao Cau Bay. The obtained data, combined with the Gao-Collins Grain Size Trend Analysis Model （GSTA model）, were used to infer the characteristics and transportation trend of sarface sediment in the Cu Lao Cau Bay,Vietnam. The results suggested that the surface sediments were mainly composed of coarse particles. Under the influences of the tidal currents and waves,the particles were coarse in the central and western part of the bay,and fine in the eastern part. In the western part of the bay, the sediments were transported from southwest into the bay along the coast. In the central part of the bay,the sediments were transported from nearshore to offshore. In the eastern part of the bay,the sediments were transported from northeast to the southwest. A convergent area of sediments was formed by the sediment from the western and eastern part of the bay,and then they moved westward under the in- fluence of residual currents. The surface sediment movement was mainly induced by the superimposed effect of wave and tidal current, of which the sediment was left by wave and transported by the tidal current. The coastline of the Cu Lao Cau Bay is being eroded under the influence of wave （a main factor） ,and it generally takes on a tend-ency of moving backward.