1992 Fiscal Year Final Research Report Summary
Hydraulic Study on Liquefaction of Water Bed due to Water Surface Variation
| Project/Area Number |
02452204
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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 |
Hydraulic engineering
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| Research Institution | MEIJO UNIVERSITY |
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Principal Investigator |
IWAGAKI Yuichi Meijo University, Faculty of Science & Technology, Professor, 理工学部, 教授 (90027201)
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| Co-Investigator(Kenkyū-buntansha) |
HARADA Morihiro Meijo University, Faculty of Science & Technology, Instructor, 理工学部, 講師 (40165030)
ARAI Muneyuki Meijo University, Faculty of Science & Technology, Instructor, 理工学部, 講師 (90103259)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Liquefaction of water bed / Settlement of heavy mass / Pore water pressure / Net settlement of body / Compaction of sand bed / Debris flow of muddy type / Sedimentation process / 構造物の鉛直変位 |
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| Research Abstract |
1. Liquefaction on sea bed : First of all, an experimental tank for reproducing actual sea beds in a laboratory was made by using lucid acrylic plates of 1 cm thickness. However, because of a short age of rigidity, a second tank was equipped by steel plate of 1 cm thickness with a generator of water pressure variation. The first test was to measure vertical distributions of pore pressure in the sand bed and vertical displacement of a lead cylindrical mass set on the sand bottom due to water pressure variation. The main results of the tests are as follows : (1) Vertical displacement of the sand bed itself occurs due to periodic water pressure variation, but its deformation is elastic, so that the position of sand bottom comes back again after one period of variation. (2) Vertical displacement of the heavy mass set on the sand bottom is not periodical change and not complete elastic, but shows plastic behavior. (3) The residual displacement after one period is a net settlement of the heavy mass per one wave. (4) The reason of the plastic behavior of a water sandbed is not clear whether by liquefaction or not. This is a further problem to be solved.
2. Liquefaction on river bed : It makes to clear that a numerical simulation method for the deposition of the mud flow with high content of fine and cohesionless sediment. The model assumes that the excess guantity of sediment than the equilibrium deposits with the settling velocity. And in the case the debris and mud flows flow in a reservoir, it occurs a density flow or to deposit the sediment near the shallow water. It is dominated by the condition of the suspension of particles.
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