海底边界层沉积物再悬浮的研究进展

RESUSPENSION OF SEDIMENTS ALONG THE BOTTOM BOUNDARY LAYER:A REVIEW

海床沉积物受海洋水体的影响形成海底边界层(Bottom Boundary Layers,BBLs)。上部海水与下部沉积物在BBLs发生着复杂的相互作用,直接影响海底沉积物侵蚀、再悬浮与堆积过程。与此同时,沉积物颗粒可能携带的污染物解析释放,BBLs研究的科学意义与工程应用价值日益突显。海底边界层的范围已经远远超出了传统的流体力学中边界层的范围,而是海床界面上下一定范围内,水流与海床相互作用的区域。在波浪作用下BBLs沉积物以海床剪切破坏、海床液化破坏及震荡体破坏三种破坏模式发生侵蚀再悬浮。此外,海流、风暴潮、人类活动以及海底生物的扰动作用等对沉积物再悬浮起着不可忽视的作用。BBLs沉积物再悬浮原位观测是研究BBLs沉积物再悬浮最基础也是最重要的手段之一,常用的原位测试手段有水体采样、OBS、激光粒度仪、ADCP/ADV以及电法测量。海底悬沙和底沙的交换程度直接影响底层悬沙浓度的变化,沉积物再悬浮的定量分析成为海洋沉积过程研究的主要内容之一。系统地总结前人的研究成果,重点围绕海底边界层理论、海底沉积物再悬浮的影响因素、沉积物再悬浮的原位观测以及海底沉积物再悬浮的定量分析等几个问题进行综合评述。

The bottom boundary layer（BBLs）is a complex interaction layer between seawater and bottom sediment,which affects the erosion,re-suspension and deposition of sediments.Some pollutants carried by sediment particles may be released into the water during the processes.Therefore,studying the BBLs has become increasingly important in both scientific significance and the practical application.The scope of the bottom boundary layers,in our concern,is far beyond the range of the boundary layer in traditional fluid mechanics,it is defined hereby as the part of seabed interface where the currents and seabed sediment interact.The sediment suffers from erosion and re-suspension under the action of the waves through the following three failure modes：seabed shear failure,seabed liquefaction and shock destruction.In addition,ocean currents,storm surge,human activities and the disturbance of sea creatures play certain roles which should not be ignored for sediment re-suspension.The in-situ observation of sediment re-suspension is one of the most basic and important methods for research of sediment re-suspension,which include water sampling,OBS,LISST-100,ADCP/ADV and the electrical measurement.The exchange between the suspended sediment and the bottom sediment directly affect the changes in suspended sediment concentration.Quantitative analysis of sediment re-suspension has become one of the main research topics of marine sedimentation.The paper systematically analyzed and summarized the achievements of previous researchers.On the basis of the comprehensive review focusing on the bottom boundary layer theory,the influence factors of seabed sediment re-suspension,the in-situ observation of sediment re-suspension and the quantitative analysis of seabed sediment re-suspension are also discussed.The work will provide references for further researches.