人工砾石海滩变化及输移率研究

Study on evolution and transport rate of artificial gravel beach

在我国采用砾石海滩在某些强动力区域进行海滩养护是一种新的尝试,具有很好的适用性。以厦门天泉湾人工砾石滩为研究对象,对2015年至2016年间10条海滩剖面开展了5次周期性监测,通过综合分析,得出在人工砾石滩竣工完成后的一年时间内,滩肩外沿线、岸线及滩面底角的砂砾分界线大幅度后退,滩肩宽度变窄;滩肩外沿线明显隆起,形成滩肩脊线;滩面坡度变大,且上游侧海滩的滩面普遍比下游侧海滩的滩面陡,一年后,岸滩整体变化趋于稳定。针对砾石滩不断向西南方向运移的现状,采用Leo C.van Rijn输移率公式计算砾石滩年平均输移率,并通过测量断面法、体积变化量法对Leo C.van Rijn公式计算结果进行验证,得出砾石滩年平均输移率的范围约为1 015.66~2 392.5 m^3/a。

The adoption of the artificial gravel beach in macro-tide and strong hydrodynamic coast is a new attempt of beach protection in China. During the period between 2015 and 2016,ten beach profiles were measured and five regular monitoring activities were conducted along the beach in Tianquan Bay,Xiamen. The results indicate that the edge of beach berm,shoreline and the boundary of gravel and sand changed obviously one year after the completion of the artificial gravel beach project. The width of beach berm became narrower,the elevation of berm crest increased with a dome formation,and the beach slope became steeper and showed a variation that the beach slope in the upstream became steeper than it in the downstream. After one year’s evolution,the beach morphology tended to be stable. To study the gravel transportation of the artificial gravel beach,the Leo C. van Rijn formula was used to calculate the average annual transport rate,and the result was verified by beach profile measurement and volume change. The result shows that the annual average transport rate of gravel beach is about 1 015.66 ~ 2 392.5 m3/a.