底开驳船抛投土沙水下运动特性室内试验研究  

Laboratory experiments study on underwater movement characteristics of sand dumped from hopper barge

作　　者：狄鑫平 刘鹏 蒋勤[1] 应铭 DI Xinping;LIU Peng;JIANG Qin;YING Ming(College of Harbor,Coastal and Offshore Engineering,Hohai University,Nanjing 210098,China;Shanghai Waterway Engineering Design and Consulting Co.,Ltd.,Shanghai 200120,China)

机构地区：[1]河海大学港口海岸与近海工程学院,江苏南京210098 [2]中交上海航道勘察设计研究院有限公司,上海200120

出　　处：《人民长江》2021年第8期222-229,共8页Yangtze River

基　　金：国家重点研发计划项目(2017YFC0405400)。

摘　　要：揭示抛投土沙的水下运动特性对指导疏浚土的水下抛投作业等具有重要意义。通过对底开驳船抛投土沙的室内物理模型试验研究,分析土沙的水下运动过程及其运动特性。以塑料沙、粉煤灰和长江口航道淤泥为研究对象进行静水抛投试验,分析泥沙粒径、含水率、黏性以及投放水深对抛投无黏性和黏性土沙水下运动特性的影响。采用长江口航道疏浚淤泥进行单向动水抛投试验,分析抛投黏性土沙床面落淤存留率与水流流速之间的定量关系。结果表明:黏性与无黏性抛投土沙在水下的运动过程均可分为拥挤下落、对流沉降、悬移输送、触底崩散和水平扩散5个阶段;泥沙的粒径越大、含水率越低或投放水深越大,泥沙的水下沉降速度越快;单向动水环境下,水流流速越大,现场疏浚淤泥的床面落淤存留率越低,通过对试验数据的回归分析给出了床面存留率与水流流速间的经验关系公式。Understanding the underwater movement characteristics of sand dumped from hopper barge is of great importance to the disposal operation of dredged material in channel engineering.Through laboratory physical model experiments on the sand dumped from hopper barge,we clarify the underwater movement process and characteristics of disposed sand.Firstly,we use plastic sand,fly ash,and the dredged silt from Changjiang River Estuary channel as model materials to conduct sand disposal experiments in still water.The experiment results demonstrate the influence of particle size,water content ratio,viscosity and water depth on the underwater movement characteristics of viscous and inviscid sand.In addition,we carry out sand disposal experiments with the dredged silt from the Changjiang River Estuary channel in unidirectional flow to analyze the quantitative relationship between the current velocity and silt deposition remaining rate on bed.The experiment results indicate that both the underwater movement process of viscous and inviscid disposed sand can be divided into five stages,i.e.,crowded falling,convection settlement,suspended transportation,disintegration at the bottom and horizontal diffusion.The sand settlement speeds up with the enlargement of sediment particle size,the decrease of water content ratio,or the increment of water depth.In unidirectional flow environment,the silt deposition remaining rate on bed declines as the current velocity increases.A empirical relation formula is constituted through regression analysis of the experiment data,which describes the quantitative relationship between the silt remaining rate on bed and current velocity.

关 键 词：土沙投放 运动特性 疏浚土 底开驳船 抛投土沙床面存留率 

分 类 号：TV149[水利工程—水力学及河流动力学]