摘要
细颗粒泥沙沉降特性受粒径、级配、含盐度、矿物等多因素影响,沉降中是否发生絮凝是选用泥沙运动计算理论的关键。针对单一矿质泥沙絮凝沉降特性,基于静水沉降实验,研究粒径、级配与含盐度对石英质粉砂沉速的影响。实验研究发现,石英质粉砂在清水和盐水中均可絮凝。清水中,石英质粉砂絮凝临界粒径在8μm左右,絮凝指标大于4。盐水可提高絮凝粒径上限至40μm,但不同粒径颗粒絮凝指标分异,其中颗粒絮凝最优含盐度为15 ppt。级配是影响石英质粉砂沉降的关键因子,若小于8μm组分含量超过8%,细颗粒不仅可与同粒径颗粒形成絮团,还可附着粗颗粒,增大沙样沉速。研究结果可丰富细颗粒泥沙絮凝沉降理论,为研究复杂物质构成泥沙沉降规律提供依据。
Settling processes of fine-grain sediment are influenced by particle size,sediment composition,minerals and water salinity.Flocculation is one of keys to distinguish theories for estimation of sediment transport.This study focuses on flocculation settling features of quartz silts by series of settling experiment in still water to understand the influence of particle size,sediment composition and water salinity on settling processes.The results indicate that the quartz silt can flocculate in both fresh water and salt water.In fresh water,the critical particle size for flocculation is about 8μm,with corresponding flocculation index greater than 4.Salinity can increase the upper limit of particle size for flocculation to 40μm,and the flocculation index varies with particle size.The optimum salinity for flocculation is 15 ppt.Sediment composition is the key factor controlling the settling feature of quartz silt.If the content of particles smaller than 8μm exceeds 8%,the fine particle can not only form flocs with its counterparts,but also adhere to the coarse particles,enhancing the overall settling velocity of the mixtures.
作者
姚鹏
孙维
郭千秋
苏敏
YAO Peng;SUN Wei;GUO Qian-qiu;SU Min(State Key Laboratory of Hydrology,Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China;Jiangsu Key Laboratory of Coast Ocean Resources Development and Environment Security,Hohai University,Nanjing 210098,China;College of Harbor,Coastal and Offshore Engineering,Hohai University,Nanjing 210098,China;State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China;State Key Laboratory of Coastal and Offshore Engineering,Dalian University of Technology,Dalian 116024,China)
出处
《泥沙研究》
CAS
CSCD
北大核心
2022年第5期15-22,共8页
Journal of Sediment Research
基金
国家自然科学基金项目(51809296,51709288)
河口海岸学国家重点实验室开放基金资助项目(SKLEC-KF202006)
中央高校基本科研业务费项目(2019B05914)
大连理工大学海岸和近海工程国家重点实验室开放基金资助项目(LP2207)
国家自然科学基金项目(51620105005)
江苏省“双创博士”项目(2020-30459,2020-30454)
江苏省大学生创新创业训练计划(202010294119Y)。
关键词
石英质粉砂
沉降
级配
含盐度
絮凝
quartz silt
settling
sediment composition
water salinity
flocculation
