盐水环境下细颗粒淤泥的起动试验研究  

Experimental study on incipient motion of newly deposited fine sediment under different saline conditions

作　　者：刘欣 张晓雷 吴浩然 刘书瑜 LIU Xin;ZHANG Xiao-lei;WU Hao-ran;LIU Shu-yu(School of Water Conservancy,North China University of Water Resources and Electric Power,Zhengzhou 450046,China)

机构地区：[1]华北水利水电大学水利学院,河南郑州450046

出　　处：《水运工程》2022年第3期14-20,共7页Port & Waterway Engineering

基　　金：国家自然科学基金资助项目(41930643);水利部珠江河口动力学及伴生过程调控重点实验室开放研究基金项目([2018]KJ06)。

摘　　要：为掌握细颗粒淤泥在盐水环境下的起动规律,利用可循环水槽开展盐水0‰泥(仅水体含盐)、盐水盐泥(水体和泥沙均含盐)和0‰水盐泥(仅泥沙含盐)3个系列的泥沙起动水槽试验。基于PIV(粒子图像测速)系统和数字图像灰度处理技术实现泥沙起动流速的定量判别。结果表明:水体或黏性泥沙的含盐度越高,黏性泥沙越难起动。黏性泥沙起动流速与水体盐度或泥沙盐度呈对数关系,盐度0‰~10‰范围内起动流速急剧增大,10‰~40‰范围内缓慢增大。对于同一含盐度而言,0‰水盐泥的起动流速最大,盐水盐泥起动流速次之,盐水0‰泥起动流速最小。含砾粉砂质淤泥在盐水环境下会发生絮凝现象,以520 r/min的速率搅拌会使含盐的粉砂质淤泥发生絮散,盐度对粉砂质淤泥的起动影响甚微。To master the incipient motion of newly deposited fine sediment under different saline conditions, we carry out three series of mud incipient tests with circulating flume, including salt-free mud incipient motion tests in saltwater(saltwater-salt-free mud),salt mud incipient motion tests in saltwater(saltwater-salt mud),and salt mud incipient motion tests in freshwater(freshwater-salt mud). On the basis of the particle image velocimetry(PIV)system and digital image gray processing technology, we identify quantitatively the critical incipient velocity of sediment. The results show that the higher salinity of water body or cohesive sediments makes it more difficult to start. There is a logarithmic relationship between the incipient velocity of cohesive sediments and the salinity of water or cohesive sediments. The incipient velocity increases sharply at the salinity of 0‰-10‰ and slowly at the salinity of 10‰-40‰. For the same salinity, the incipient velocity of salt mud in freshwater is the highest, followed by that of salt mud in saltwater, and that of salt-free mud in saltwater is the lowest. For sandy silt mixtures containing gravel, it is easy to flocculate in saltwater. However, the flocs are easy to disperse under high-speed stirring at 520 r/min, so salinity has little effect on the incipient motion of sandy silt.

关 键 词：黏性泥沙 泥沙起动 盐度 淤泥质黏土 砂质粉土 

分 类 号：TV142.1[水利工程—水力学及河流动力学]