Determination of the suspension competence of debris flows based on particle size analysis  

作　　者：Hong-juan YANG Fang-qiang WEI Kai-heng HU Chuan-chang WANG 

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：《International Journal of Sediment Research》2014年第1期73-81,共9页国际泥沙研究（英文版）

基　　金：supported by the National Basic Research Program of China(973 Program)(No.2011CB409902);National Natural Science Foundation of China(No.41201011);the Youth Talent Team Program of Institute of Mountain Hazards and Environment,CAS(No.SDSQB-2010-01)

摘　　要：The determination of the critical particle size between solid and fluid phases, i.e., the suspension competence, is fundamental for debris flow. A method for determining suspension competence based on particle size analysis is presented in this paper. Suspension competence of static experimental water-debris mixtures prepared with the sediment of Jiangjia Gully is -0.025 mm if the bulk density is less than 1,800 kg m-3 and it increases with bulk density of more concentrated mixtures. Suspension competence of natural debris flows in Jiangjia Gully increases exponentially with the bulk density. These two data sets are compared in order to understand the suspension mechanism. It is concluded that turbulence may play a leading role in particle suspension in non-viscous and sub-viscous debris flows, while in viscous debris flows both matrix strength and excess pore water pressure play important roles.The determination of the critical particle size between solid and fluid phases, i.e., the suspension competence, is fundamental for debris flow. A method for determining suspension competence based on particle size analysis is presented in this paper. Suspension competence of static experimental water-debris mixtures prepared with the sediment of Jiangjia Gully is -0.025 mm if the bulk density is less than 1,800 kg m-3 and it increases with bulk density of more concentrated mixtures. Suspension competence of natural debris flows in Jiangjia Gully increases exponentially with the bulk density. These two data sets are compared in order to understand the suspension mechanism. It is concluded that turbulence may play a leading role in particle suspension in non-viscous and sub-viscous debris flows, while in viscous debris flows both matrix strength and excess pore water pressure play important roles.

关 键 词：Debris flow Suspension competence Particle size analysis Critical particle size Particle suspensionmechanism 

分 类 号：P642.23[天文地球—工程地质学]