摘要
泥沙的起动是涉水泥沙研究中最基本的问题,由于黏性泥沙的特性复杂,其起动临界条件仍是待揭示的热点问题。通过水槽试验研究了不同流化状态的泥沙样本的起动,分析了含水率、屈服应力、中值粒径等对黏性泥沙起动流速的影响。结果表明:受外部动荷载扰动时,相同含水率的泥沙可能呈现显著差异的起动流速;实质上,相同粒径级配的黏性泥沙的起动流速由屈服应力决定性控制,二者构成确定性单值映射关系;黏性泥沙的起动流速会随屈服应力的增加而指数性上升,但其增幅随泥沙中值粒径的增大而逐渐减小。根据试验结果,提出了包含流变项和重力项的粘性泥沙起动流速公式,以期为水下泥沙运动的理论分析及相关工程设计提供参考。
The incipient motion of sediments is a fundamental issue in submerged sediment research.Owing to the complex characteristics of cohesive sediments,theircritical conditions for incipient motion remain a focal topic requiring further elucidation.In this paper,the incipient motion of cohesive sediment samples under various fluidization states was investigated through flume tests,and the effects of water content,yield stress,and median particlesize on the incipient velocity were analyzed.The results indicate that sediments with identical water content may exhibit significant divergence in incipient velocity under dynamic external shear loading perturbations.For cohesive sediments with identical particle size distributions,the incipient velocity is governed primarily by the yield stress,establishing a one-to-one correspondence.Furthermore,the incipient velocity increases exponentially with increasing yield stress,while the growth rate decreases with larger median particle size.Based on the experimental findings,an empirical formula incorporating rheological and gravitational terms was proposed for predicting the incipient velocity of cohesive sediments,which is expected to provide a reference for the theoretical analysis of underwater sediment motion and related engineering design.
作者
左晶晶
喻国良
张民曦
ZUO Jingjing;YU Guoliang;ZHANG Minxi(Power China Zhongnan Engineering Corporation Limited,Changsha 410014,China;Key Laboratory of Marine Intelligent Equipment and System,Ministry of Education,Shanghai Jiao Tong University,Shanghai 200240,China)
出处
《水道港口》
2026年第1期25-32,共8页
Journal of Waterway and Harbor
基金
国家自然科学基金项目(52001206)。
关键词
黏性泥沙
泥沙起动
起动流速
泥沙流变
屈服应力
流化
cohesive sediment
incipient motion
incipient velocity
sediment rheology
yield stress
fluidization
