破碎波作用下沙质海床床面形态变化试验  

An experimental study on profile changes of sandy seabed under breaking waves

作　　者：程永舟[1,2] 潘昀[1,3] 蒋昌波[1,2] 李青峰[1] 

机构地区：[1]长沙理工大学水利工程学院,湖南长沙410004 [2]水沙科学与水灾害防治湖南省重点实验室,湖南长沙410004 [3]南京水利科学研究院港口航道泥沙工程交通行业重点实验室,江苏南京210029

出　　处：《水科学进展》2014年第2期253-259,共7页Advances in Water Science

基　　金：国家自然科学基金资助项目(41176072;51239001)~~

摘　　要：波浪在斜坡沙质海床上破碎会加剧泥沙输移导致海床形态变化,研究破碎波作用下沙质海床形态变化机制对于岸滩演变分析极为重要。在波浪水槽中采用中值粒径0.47 mm原型沙铺设1∶20坡度的底床模型进行试验研究,测量不同波浪条件下床面形态和沙坝顶端悬浮泥沙浓度变化。通过测量和计算破碎带输沙率、沙坝尺度和沙坝移动速度,分析破碎波作用下沙质斜坡海床上床面形态变化规律。试验结果表明,破碎带沙坝顶端的悬浮泥沙浓度与水深和底部床面密切相关,在形成沙坝和沙坝水平方向移动时,悬浮泥沙浓度较大;斜坡上沙坝前后来回运动的周期大小具有随机性,沙坝既有向岸又有离岸移动;在多组波长时间作用后沙坝尺度趋于稳定,底床净输沙量趋于0。Sediment transport induced by wave breaking on the sandy sloping seabed leads to bed profile changes. Research on the mechanism of sandy seabed morphology change under the action of breaking waves is of great important to analyze the beach evolution. Experiments in this study are carried out in a wave flume on a 1：20 sloping artificial seabed, which is made of sands with median diameter of 0.47mm. The bed profile variations and the suspended sediment concentration on the top of the sandy bar are measured. By calculating the sediment transport rate in the surf zone as well as the dimensions and moving speed of the sandbar, the evolution of the seabed profile under breaking waves is analyzed. Experimental results show that the suspended sediment concentration in the surf zone on top of the sandbar is closely related to the local water depth and bed morphology. The concentration of the suspended sediment is larger when the sandbar forms and moves horizontally. There are both onshore and offshore movement of the sandbar and the back-and-forth movement of the sandbar on the slope have a random period. The dimensions of the sandbar tend to be stable and the net sediment transport tends to be zero under the action of wave trains. The result provides a reference for further study on the beach evolution.

关 键 词：破碎波 床面形态 悬浮泥沙浓度 泥沙输移 

分 类 号：TV139.2[水利工程—水力学及河流动力学]