低能砂质海岸人工水下沙坝剖面的演变分析

Analysis of the evolution of beach profiles in a low-energy sandy beach with a submerged berm

人工水下沙坝因为其环境友好性越来越多地被用于人工养滩。该文对秦皇岛低能海滩的实测养滩剖面数据进行分析表明:海滩剖面可分为始终保持相对稳定的背景剖面和不断演变的滩肩和人工水下沙坝剖面;工程后人工水下沙坝向海侧逐渐变缓,向陆侧逐渐变陡,剖面形状发生明显的不对称性演变。该文采用经验正交函数分析方法(EOF)对海滩剖面演变过程进行分析,得到的前三个特征函数分别对应于平均海滩剖面、滩肩和水下沙坝的体积改变以及水下沙坝形状的非对称性演变。该研究可为低能砂质海岸地貌动力的研究和相关工程提供参考依据。

The submerged berm is an increasing used method for beach nourishment due to its eco-friendly nature.A beach nourishment project was carried out on a low energy Beach,in Qinhuangdao,China.An analysis of its beach profile evolution indicates that the background of the beach profiles keep relatively stable,while the berm nourishment and submerged berms evolved on the background.The cross-shore profiles of the submerged berm have shown a significant shape changing to an asymmetrical shape,whose seaward slope becomes gentler and landward slope becomes sharper.Empirical orthogonal function analysis is conducted in this paper and the results confirm the features of the background-berms pattern gained from the evolution analysis.The first three eigenfunctions correspond to the mean beach profile,volume changes of the berm and submerged berm,and the asymmetrical shape changing of the submerged berm respectively.The study contributes to the understanding of the cross-shore beach morphodynamics and can provide reference for beach nourishment under similar conditions.