波浪作用下沙质海滩沉积物运动特征

发布时间：2018-03-11 12:49

本文选题：沙质海滩　切入点：海滩演化　出处：《应用基础与工程科学学报》2016年02期 　论文类型：期刊论文

【摘要】：基于二维波浪水槽实验,采用沙质斜坡概化海滩,分别选用规则波和椭圆余弦波进行实验,测量波浪作用前后的海滩剖面形态及断面沉积物粒径组成,探讨波浪作用下沙质海滩沉积物运动特征,包括剖面形态演化特征及其床沙分选规律.结果表明:沙质海滩剖面形态时空演化特征受波浪类型、波高、周期等因素影响,呈现出沙坝形态和滩肩形态,发现波浪Irribarren参数可以作为沙质海滩剖面演化形态的判别参数.在本实验条件下,Irribarren参数大,海滩剖面呈现滩肩形态;Irribarren参数小,海滩剖面则呈现沙坝形态.海滩床面沉积物在波浪作用下产生了明显的分选现象,波浪破碎产生的强烈紊动造成床面沉积物的起动、并为小颗粒的运动提供动力.水体紊动导致水流挟沙力降低,大颗粒泥沙在紊动较强区域产生沉积,部分被水流挟带发生向岸推移;小颗粒泥沙则随水流运动,在紊动较弱的区域分散沉积.
[Abstract]:Based on 2-D wave flume experiment, sand slope was used to generalize the beach. Regular wave and elliptical cosine wave were used to measure the beach profile and sediment size composition before and after wave action. The characteristics of sediment movement in sandy beach under wave action, including the characteristics of profile morphology evolution and bed sediment sorting, are discussed. The results show that the spatial and temporal evolution characteristics of sand beach profile are affected by wave type, wave height, period and so on. It is found that the wave Irribarren parameter can be used as a discriminant parameter for the evolution of sandy beach profile. Under the experimental conditions, the Irribarren parameter is large and the beach profile is small. The beach section shows the sand dam shape. The beach bed sediment has obvious sorting phenomenon under the action of the wave, and the strong turbulence caused by the wave breaking causes the bed surface sediment to start. It also provides power for the movement of small particles. Turbulence results in the decrease of sediment carrying capacity of water flow, the deposition of large sediment in the turbulent region, and the moving of small sediment along with the water flow, some of which are carried ashore by the flow of water. The deposits are dispersed in the less turbulent regions.
【作者单位】：长沙理工大学水利工程学院水沙科学与水灾害防治湖南省重点实验室;
【基金】：国家自然科学基金重点项目(51239001);国家自然科学基金项目(51179015,51409022,50979008)
【分类号】：TV148

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