1994 Fiscal Year Final Research Report Summary
On the limit and rate of erosion of river bank
| Project/Area Number |
05452243
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
水工水理学
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| Research Institution | HIROSHIMA UNIVERSITY (1994)
Tokyo Institute of Technology (1993) |
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Principal Investigator |
FUKUOKA Shoji Department of Civil and Environmental Engineering, Hiroshima Univ.Professor, 工学部, 教授 (30016472)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEMURA Jiro Department of Civil Engineering, Tokyo Inst.of Technology, Associate Professor, 工学部, 助教授 (40179669)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Natural bank / Overhanging and Collapse / Countermeasure / Failure of embankment / Centrifuge model test / Field Test |
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| Research Abstract |
Silt channel and clay channel were dug on the flood plain of the Ara river and Rokkaku river, respectively, where erosion rate of bed and bank were investigated in detail. Erosion process of silt channel consists of formation of overhanging bank, collapse, and transport. Analytical model which provides physical explanation was constructed. Erosion process of clay bank was influenced by water content, density, and clay sedimentation process. Evaluation of these effects on erosion rate was attempted. Critical length at the instant when the overhanging bank is about to collapse was estimated. The countermeasure against the bank erosion was studied in the aspect of hydraulics : installation of vane array, utilization of live vegetation beside the bank such as reed, making the bank gentler. We developed a basis of technology and learning for protection method corresponding to hydraulic condition and bank soil condition by synthesizing of these knowledge.
Two series of centrifuge model tests were carried out to investigate the stability of loose embankments subjected to a seepage flow. One is a modelling of prototype for an unreinforced embankment with the prototype height of 3.5m under 25g and the other is tests for embankments reinforces with piles under different conditions of pile density and protile of water surface. Observed behavior in the model embankment was very similar to that in the large scale 1g model. It was found that the deformation at the initial stage cannot be prevented by reinforcement with pile, however the catastrophic failure followed by the deformations can be prevented by the reinforcement.
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