黏性泥沙的物理特性与起动应力的流变学分析  

Influences of physical properties of cohesive sediment on threshold shear stress based on rheological method

作　　者：王梦寒 王宪业[1] 陈思明 何青[1] WANG Meng-han;WANG Xian-ye;CHEN Si-ming;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

出　　处：《泥沙研究》2018年第6期8-14,共7页Journal of Sediment Research

基　　金：国家自然科学基金项目(41406094,51320105005,41676066);上海市科委项目(17DZ1204800);国家科技支撑计划项目(2013BAB12B05-02)

摘　　要：以长江口黏土含量15%~45%的黏性泥沙为研究对象,采用MCR302流变仪,系统研究泥沙的物理特性包括盐度、黏土含量和含水率对流变特性的影响。结果表明:盐度的变化对黏性泥沙的黏度影响较大,对屈服应力影响较小,屈服应力最大变幅为±4%;黏土含量增加使黏性和屈服应力均增大;低含水率(小于28%)时随含水率的增大泥沙流变特性增强,高含水率(大于28%)时随含水率的增大黏性泥沙的流变特性减弱且黏度减小,屈服应力随含水率增大而先增大后减小;起动应力随含水率的增大先增大后减小。基于对泥沙物理特性与屈服应力的相关性研究,建立了基于含水率的黏性泥沙的起动应力公式。Influences of salinity,clay content and water content on rheological properties of cohesive sediment were studied by MCR302rheometer.Experimental sediment were collected from Yangtze River Estuary with clay content of 15%-45%.Results show that the salinity has a great influence on the viscosity and less effect on the yield stress,in which the variation range of yield stress is within ±4%.With the increase of clay content,the viscosity and yield stress increased.Under low water content (less than 28%)condition,the theological properties-of sediment increase withthe increase of water content.However,with the increase of water content,the theological properties and the viscosity decreased,and the yield stress increased at first and then decreased under high water content (greater than 28%)condition.The threshold shear stress increased at first and then decreased with the increase of water content.Based on the effects of the physical properties on the yield stress,a formula to estimate the threshold shear stress of cohesive sediment based on water content has been proposed.

关 键 词：黏性泥沙 含水率 屈服应力 起动应力 

分 类 号：TV142.1[水利工程—水力学及河流动力学]