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Journal of Mountain Science

, Volume 13, Issue 6, pp 971–984 | Cite as

Experimental study of entrainment behavior of debris flow over channel inflexion points

  • Kai-heng HuEmail author
  • Li Pu
  • Xie-kang Wang
Article

Abstract

On-spot observation and field reconnaissance of debris flows have revealed that inflexion points in the longitudinal profile of a movable channel may easily become unstable points that significantly affect their entrainment behavior. In this study, small-scale flume experiments were performed to investigate the entrainment characteristics of debris flows over two types of inflexion points, namely, a convex point, which has an upslope gradient that is less than the downslope gradient; and a concave point, which has an upslope gradient that is greater than the downslope gradient. It was observed that when debris flowed over a convex point, the entrainment developed gradually and progressively from the convex point in the downstream direction, and the primary control factors were the slope gradient and friction angle. Conversely, when debris flowed over a concave point, the entrainment was characterized by impacting and impinging erosion rather than traditional hydraulic erosion, and the impingement angle of the flow significantly determined the maximum erosion depth and outflow exit angle. An empirical relationship between the topography change and the control factors was obtained from the experimental data.

Keywords

Debris flow Entrainment Inflexion points Erosion Impingement angle 

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Copyright information

© Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Key Laboratory of Mountain Hazards and Earth Surface ProcessesChinese Academy of SciencesChengduChina
  2. 2.Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences & Ministry of Water ConservancyChengduChina
  3. 3.University of Chinese Academy of SciencesBeijingChina
  4. 4.State Key Laboratory of Hydraulics and Mountain River EngineeringSichuan UniversityChengduChina

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