Mean Velocity Estimation of Viscous Debris Flows  

作　　者：Hongjuan Yang Fangqiang Wei Kaiheng Hu 

机构地区：[1]Key Laboratory of Mountain Hazards and Earth Surface Process,Chinese Academy of Sciences [2]Institute of Mountain Hazards and Environment,Chinese Academy of Sciences

出　　处：《Journal of Earth Science》2014年第4期771-778,共8页地球科学学刊（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 41201011);the Key Research Program of the Chinese Academy of Sciences (CAS) (No. KZZD-EW-05-01);the Youth Talent Team Program of Institute of Mountain Hazards and Environment, CAS (No. SDSQB-2013-01)

摘　　要：The mean velocity estimation of debris flows, especially viscous debris flows, is an important part in the debris flow dynamics research and in the design of control structures. In this study, theoretical equations for computing debris flow velocity with the one-phase flow assumption were reviewed and used to analyze field data of viscous debris flows. Results show that the viscous debris flow is diffficult to be classified as a Newtonian laminar flow, a Newtonian turbulent flow, a Bingham fluid, or a dilatant fluid in the strict sense. However, we can establish empirical formulas to compute its mean velocity following equations for Newtonian turbulent flows, because most viscous debris flows are tur- bulent. Factors that potentially influence debris flow velocity were chosen according to two-phase flow theories. Through correlation analysis and data fitting, two empirical formulas were proposed. In the first one, velocity is expressed as a function of clay content, flow depth and channel slope. In the second one, a coefficient representing the grain size nonuniformity is used instead of clay content. Both formulas can give reasonable estimate of the mean velocity of the viscous debris flow.The mean velocity estimation of debris flows, especially viscous debris flows, is an important part in the debris flow dynamics research and in the design of control structures. In this study, theoretical equations for computing debris flow velocity with the one-phase flow assumption were reviewed and used to analyze field data of viscous debris flows. Results show that the viscous debris flow is diffficult to be classified as a Newtonian laminar flow, a Newtonian turbulent flow, a Bingham fluid, or a dilatant fluid in the strict sense. However, we can establish empirical formulas to compute its mean velocity following equations for Newtonian turbulent flows, because most viscous debris flows are tur- bulent. Factors that potentially influence debris flow velocity were chosen according to two-phase flow theories. Through correlation analysis and data fitting, two empirical formulas were proposed. In the first one, velocity is expressed as a function of clay content, flow depth and channel slope. In the second one, a coefficient representing the grain size nonuniformity is used instead of clay content. Both formulas can give reasonable estimate of the mean velocity of the viscous debris flow.

关 键 词：debris flow VELOCITY one-phase flow two-phase flow viscous. 

分 类 号：P642.23[天文地球—工程地质学]