海啸波作用下泥沙运动——Ⅱ.床沙组成变化分析  

Study of sediment transport by tsunami waves: Ⅱ.Sorting of sand grains on seabed

作　　者：蒋昌波[1,2] 陈杰[1,2] 程永舟[1,2] 邓斌[1,2] 隆院男[1,2] 

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

出　　处：《水科学进展》2012年第6期802-807,共6页Advances in Water Science

基　　金：国家自然科学基金资助项目(51239001;51179015)~~

摘　　要：在波浪水槽实验的基础上,对海啸波作用下的床沙组成变化规律开展研究。实验采用1/10～1/20的组合坡度,选取N波作为入射波。实验对波高进行采集,对波浪的上爬、回落和水跃过程进行拍摄记录,对每个波作用后的地形进行测量,并对初始和最终的床面顶层泥沙进行采样筛分。实验结果表明,N波作用下泥沙在离岸区水跃发生区域堆积,淤积沙坝泥沙粒径呈粗化趋势。同时采用规则波和非规则波进行对比,波浪作用后形成岸滩也为沙坝剖面,淤积沙坝泥沙粒径呈细化趋势,结果均遵循elikogˇlu提出的泥沙运动的基本规律,细颗粒泥沙会在强烈的紊动作用下从床面中被筛选出来,并被搬运到低紊动地区,此过程造成了剧烈紊动区泥沙的粗化。The devastating tsunami waves can mobilize a substantial amount of coastal sediments and considerably change the coastal morphology. Meanwhile, the study of grain size sorting on seabed is not only the core content for non-uniform sediment transport but also the key scientific issue in the study of sediment transport mechanics. A two- dimensional laboratory experiment is conducted to investigate the distribution change of sediment grain sizes under the influence of waves. The initial beach slope of 1/10 - 1/20 is exposed to the action of N-waves. The wave free surface elevations, processes of wave uprush, back wash and run-down jump, the change of cross-shore beach profile, the in- itial and final distribution of sediment grain sizes are observed and measured. Results show that there is a strong down- rush following the large run-up resulted in erosion on the foreshore and deposition seaward of wave run-down. The mean grain size increases in the deposition area. The beach profiles show bar type under regular and irregular wave actions in the experiment. The mean grain size decreases in the deposition area. This experimental result is in accord with the findings of （~eliko^lu that finer grains are winnowed from the seabed in most energetic areas by the turbulent process and then carried away to less energetic areas, resulting in coarsening of the median bed surface grain size in more energetic areas.

关 键 词：海啸波 非均匀输沙 床沙变化 N波 

分 类 号：TV14[水利工程—水力学及河流动力学]