EGU22-6627
https://doi.org/10.5194/egusphere-egu22-6627
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

An experimental study on effects of grain size distribution on debris flow deposition characteristics

Hiroaki Izumiyama1, Takao Yamakoshi2, Yuya Takahashi3, Yuki Nishiguchi4, and Ryosuke Okuyama5
Hiroaki Izumiyama et al.
  • 1National Institute for Land and Infrastructure Management, Tsukuba City, Japan (izumiyama-h92ta@mlit.go.jp)
  • 2National Institute for Land and Infrastructure Management, Tsukuba City, Japan (yamakoshi-t925h@mlit.go.jp)
  • 3CTI Engineering Co., LTD., Tsukuba City, Japan(yy-takahashi@ctie.co.jp)
  • 4CTI Engineering Co., LTD., Tsukuba City, Japan(nishiguchi@ctie.co.jp)
  • 5CTI Engineering Co., LTD., Tsukuba City, Japan(rsk-okuyama@ctie.co.jp)

Precise prediction of travel distance of debris flow is required to design countermeasure strategy against natural disaster. A lot of numerical simulation tools have been developed using a selected shear stress which has been modeled to express the characteristics of debris flow and a modeled entrainment ratio. However, the calculation results for past events often show underestimated travel distance. One of the possible causes of the fact may be that the effect of grain size distribution on the entrainment ratio. This is because most models have been modeled assuming debris flow is constituted by a single size particle. An entrainment ratio model involving the effect of particle size distribution may improve the calculation reproductivity. From an engineering point of view, it is desirable that the effect can be taken into account as simply as possible. In this study, we conducted an experiment to know the extent to which the entrainment ratio is affected by the grain size distribution. The experiments were undertaken in a rectangular flume the channel slope of which can be adjusted at two points in longitudinal direction. Two-size mixtures of spherical glass beads or gravels were set as debris flow material. For each mixture, travel distance of debris flow and fractions of each size of debris flow material deposited near the channel slope change point were measured using high-speed camera.

How to cite: Izumiyama, H., Yamakoshi, T., Takahashi, Y., Nishiguchi, Y., and Okuyama, R.: An experimental study on effects of grain size distribution on debris flow deposition characteristics, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6627, https://doi.org/10.5194/egusphere-egu22-6627, 2022.

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