摘要
当前对海洋沉积物再悬浮的过程的研究主要分为海洋流体的动力作用和动力作用下沉积物的动力响应过程两方面,内孤立波能够在海洋跃层间传输数百米,诱发极强的垂向流动,引起沉积物再悬浮。基于此设计水槽实验,设置土坡实验组和土层对照组,控制渗流条件的有无,进而控制海床沉积物动力响应的充分与否,通过制造下凹型内孤立波,改变海床沉积物的底质条件和内孤立波的振幅,对比分析不同条件下内孤立波浅化破碎导致的沉积物、再悬浮现象,探讨渗流条件对再悬浮过程的影响。实验发现在内孤立波作用下,流速越快,沉积物悬浮物浓度增加值和变化速率越大,悬浮物浓度的变化幅度与悬浮物浓度最大值呈正相关。具备渗流条件,动力响应充分的土坡区域,在内孤立波作用下能够维持较高的悬浮物浓度更长时间,悬浮物浓度持续变化时长明显更久,且在流速较小时,悬浮物浓度变化速率较慢。对于底质不同的沉积物,粘粒越高对内孤立波的动力响应速度越慢,具体的变化规律也有所差异。当沉积物成分为砂质粉砂时,土层区域的最大悬浮物浓度增加值总是大于土坡区域,但在作用间隙,土坡区域能够维持较高的悬浮物浓度更长时间,最大能达到土层区域的2.5倍。当沉积物成分为粘土质粉砂时,土坡区域的悬浮物浓度增加值是土层区域的1.6~2.2倍,且局部较多的粘粒会降低孔隙通道的渗透性,不利于颗粒的输运和泵送。
Current researches on the resuspension process of marine sediments were mainly divided into two aspects:the dynamic action of marine fluids and the dynamic response process of sediments under the dynamic action.Internal solitary waves can move hundreds of meters between oceanographic thermocline,which not only has horizontal flow,but also can induce extremely strong vertical flow,which further causes the migration of sediment and pollutants.Therefore,the phenomenon of sediment resuspitation caused by the internal solitary waves shoaling and propagating on the slope has attracted much attention.With the flume experiment based on the researches,the setting up sediment slope and sediment layer in the control group,with controlling seepage condition,controlled the dynamic response of seabed sediment.By making the concave type internal solitary waves,the changing of sediment grainsize composition and internal solitary wave amplitude,comparison and analysis of different internal solitary wave under the condition of shallow broken cause of sediment resuspension phenomenon,were discussed about the influence of the dynamic response process of resuspension of sediments.The main research results were found that under the action of internal solitary waves,the faster the flow rate was,the faster the sediment suspended matter concentration changed;and the increased value of suspended matter concentration presented a positive correlation trend.For sediment slope area,with seepage conditions under the action of internal solitary wave could sustain high suspended sediments concentration for a longer time;the duration of continuous change was obviously longer than that of sediment layer.And with the slower velocity,slope area after achieving the highest suspended sediment concentration,concentration change rate was less than the sediment layer.For sediments with different grainsize composition,with the more clay content,the response speed to the internal solitary waves became more slowly,and the specific variation law was also different.When sediment components were sandy silt,under the action of internal solitary wave,variation of suspended sediment concentration in layer area was larger than it in slope area.And in the gap of two waves,the duration of higher suspended sediment concentration in slope area was much longer,the maximum could reach 2.5 times of that in the layer area.When the composition of sediment was clayey silt,the increased value of suspended matter concentration in the sediment slope area was 1.6-2.2 times of that in the sediment layer area.
作者
任子茵
田壮才
贾永刚
陈天
胡乃力
REN Ziyin;TIAN Zhuangcai;JIA Yonggang;CHEN Tian(Ocean University of China,Qingdao 266100,China;Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering,Qingdao 266100,China)
出处
《海洋湖沼通报（中英文）》
CSCD
北大核心
2024年第5期9-20,共12页
Transactions of Oceanology and Limnology
基金
国家自然科学基金(42107158)。
关键词
内孤立波
坡面沉积物
再悬浮
渗流
internal solitary waves
slope sediment
resuspension
seepage
