波流联合作用下珠江磨刀门河口絮凝问题研究  

Study on sediment floc under the influence of wave-current interaction in the Modaomen Estuary of the Pearl River

作　　者：刘坤松 谭超[2] 刘锋 杨清书 

机构地区：[1]中山大学海洋科学学院河口海岸研究所,广东广州510275 [2]广东省水利水电科学研究院,广东广州510610

出　　处：《泥沙研究》2017年第6期59-65,共7页Journal of Sediment Research

基　　金：广东省水利科技创新项目(2016-21);广东省自然科学基金项目(2017A030310435);国家重点研发计划项目(2016YFC0402600);河口海岸学国家重点实验室开放课题基金项目(SKLEC-KF201409)

摘　　要：基于2013年3月29-31日河口拦门沙外固定船载和座底三脚架观测数据,分析了磨刀门河口细颗粒泥沙絮凝体发育规律及其影响因素。磨刀门河口水体中絮凝体约以62.5μm为临界粒径分成大、小絮凝体两种存在形式,且以小絮凝体组分为主;磨刀门河口水体盐度对絮凝体发育影响作用不明显,含沙量变化在一定条件下可以促进絮凝体发育;波流动力是控制絮凝体发育的主要因素,其中流速大致以0.32 m/s为临界值,波浪以0.75 m为临界有效波高,均对絮凝体的发育存在双重影响作用。波流联合动力对絮凝体发育影响较为复杂,不同阶段对絮凝体发育主控因素有所差异,磨刀门河口细颗粒泥沙的絮凝临界剪切应力约为1.25N/m2,波、流同时达到絮凝临界值时为絮凝体发育最佳条件。A field observation of fixed shipboard and benthic tripod measurements outside sediment bar in the Modaomen Estuary of the Pearl River,a typical wave-current dominated estuary,was conducted from 29 to 31 in March,2013. Based on the field investigation,floc development processes and its influencing factors were analysed. Results show that the floc can be roughly divided into two forms at grain size of 62. 5 μm,as macro floc and micro floc. The micro floc（ 〈62. 5 μm） is the dominant proportion. Analysis of the influencing factors indicates that the salinity has no significant relationship with floc size,while the turbidity can promote the floc development. Wave and current are main factors for flocculation processes. The threshold values of velocity and significant wave height for flocculation in the Modaomen Estuary are 0. 32 m/s and 0. 75 m,respectively. The result of current impact on flocculation shows that velocity,within the threshold value,has a positive correlation with floc size,but becoming negative when velocity exceeds threshold value. Wave has similar effects on the floc development. As a result,wave-current interaction is the vital factor affecting flocculation.The threshold value of bed shear-stress for flocculation is 1. 25 N/m2.

关 键 词：磨刀门河口 细颗粒泥沙絮凝 波浪 流速 临界絮凝条件 

分 类 号：TV148[水利工程—水力学及河流动力学]