Influence of particle-size segregation in multi-granular debris flow on the fluidity
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- IWATA Tomoyuki
- Chiba Prefecture, Sanbu Public Works Office
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- HOTTA Norifumi
- Faculty of Life and Environmental Sciences, University of Tsukuba
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- SUZUKI Takuro
- Sabo & Landslide Technical Center
Bibliographic Information
- Other Title
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- 混合粒径土石流における分級現象が流動特性に及ぼす影響
- コンゴウ リュウケイ ドセキリュウ ニ オケル フンキュウ ゲンショウ ガ リュウドウ トクセイ ニ オヨボス エイキョウ
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Abstract
Understanding the flow characteristics of a debris-flow front is essential for evaluating the impact force and predicting the attainable time of the debris flow. However, the fluidity of the front has not been examined experimentally for either mono- or multi-granular debris flows. This study conducted flume tests of debris flows consisting of sediment particles that were either monogranular or a mix of two diameters and compared the results with numerical simulations. Particlesize segregation was examined in the mixed-diameter experiments using a high-speed video camera and five debris-flow samples obtained from the front edge of the debris flow at ca.0.5-second intervals. The experimental and calculated results showed good agreement for the monogranular debris flows in terms of flow depth, front velocity, and fluxes, whereas disagreement was seen in the mixed-particle-size debris flows. The disagreement was thought to arise from the dominant shear stress resulting from the concentration of smaller sediment particles in the lower layer of the flow due to inverse grading detected in the body of the debris flows. Additionally, the calculated velocity of the front was underestimated compared with the actual velocity, as the particle-size segregation at the front of multi-granular debris flows did not affect the fluidity in the initial and developing phases.
Journal
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- Journal of the Japan Society of Erosion Control Engineering
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Journal of the Japan Society of Erosion Control Engineering 66 (3), 13-23, 2013
Japan Society of Erosion Control Engineering
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Details 詳細情報について
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- CRID
- 1390282680456690304
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- NII Article ID
- 10031200130
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- NII Book ID
- AN0012035X
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- ISSN
- 21874654
- 02868385
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- NDL BIB ID
- 024897312
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- Text Lang
- ja
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- Data Source
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- JaLC
- NDL
- CiNii Articles
- Crossref
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- Abstract License Flag
- Disallowed