粉砂淤泥质潮滩表层沉积物可侵蚀性研究  

Study on erodibility of surface sediment on silty mud tidal flat

作　　者：陈思明 王宪业[1] 孙健伟 何青[1] CHEN Si-ming;WANG Xian-ye;SUN Jian-wei;HE Qing(State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200062,China)

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200062

出　　处：《泥沙研究》2020年第1期45-51,共7页Journal of Sediment Research

基　　金：国家自然科学基金项目(41406094,51739005,41676066);上海科委项目(18DZ1204802,18DZ1206506).

摘　　要：以长江口潮滩表层沉积物室内人工样和野外柱样为研究对象,采用U-GEMS微观侵蚀系统,研究了泥沙颗粒组分、固结时间和生物作用对沉积物可侵蚀性的影响。结果表明:黏土含量为17. 8%~33. 7%时,沉积物可侵蚀性受黏土含量控制,总侵蚀量小;黏土含量为8. 6%~10. 7%时,总侵蚀量增大。中值粒径为7. 2~25. 9μm时,100 min内沉积物固结缓慢,2天后固结趋于稳定。盐度越大(10~40 g/L)固结越快。砂含量超过75%时,固结48 h内沉积物总侵蚀量为1. 0 kg/m^2,48 h后总侵蚀量下降64. 8%。潮滩表层沉积物可侵蚀性受黏土含量、固结程度和生物作用控制。黏土含量大于30%,生物作用强时,沉积物可侵蚀性低;植被带沉积物可侵蚀性较低,孔隙发育会显著增强表层沉积物可侵蚀性。Effects of sediment particle composition,consolidation time and biological influence on the erodibility of surficial sediment have been studied by using U-GEMS microcosm erosion system. Experiments are based on both laboratory and field samples from the tidal flats of the Yangtze estuary. Results show that: The sediment erodibility is controlled by the clay content when it is in the range of 17. 8% ~ 33. 7%,and with small total erosion mass. However,the total erosion mass increasewhen the clay content is between 8. 6% and 10. 7%.When the median particle size is between 7. 2 μm and 25. 9 μm,the consolidation deposition process is slow within 100 min and it takes 2 days when the consolidation is becoming stable. Moreover,the greater the salinity( 10 ~ 40 g/L) is,the faster the sediment consolidation would be completed. When the content of sand is higher than 75%,the total erosion mass could reach 1. 0 kg/m^2 during the first 48-hour. After 48 hours,the total erosion mass decreases significantly with the decrease rate of 64. 8%. Erodibility of tidal beach surficial sediments is controlled by sediment particle composition,consolidation and biological activities. Sediment erodibility is low when the clay content is higher than 30% and the microbial effect is strong. Moreover,the sediment erodibility can be reduced by covered vegetation. The development of the holes on the tidal flat surface can obviously enhance the sediment erodibility.

关 键 词：潮滩 可侵蚀性 微观侵蚀系统 剪切应力 

分 类 号：P737.1[天文地球—海洋地质]