2000 Fiscal Year Final Research Report Summary
Disaster prevention work of coastal structure caused by vulnerated sand bed around coastal structure under attack of stormy wave
| Project/Area Number |
11650529
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
MAENO Shiro Okayama Univ., Dept. of Environmental and Civil Eng., Associate Professor, 環境理工学部, 助教授 (20157150)
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| Co-Investigator(Kenkyū-buntansha) |
GOTOH Hitoshi Kyoto Univ., Dept. of Civil Eng., Associate Professor, 大学院・工学研究科, 助教授 (40243068)
NAGO Hiroshi Okayama Univ., Dept. of Environmental and Civil Eng., Professor, 環境理工学部, 教授 (00034348)
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| Project Period (FY) |
1999 – 2000
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| Keywords | water pressure variation / sand bed / liquefaction / buried submarine pipe / distinct element method / finite element method / back-filling sand of revetment / interaction of element |
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| Research Abstract |
It is well known that a cyclic transient liquefaction of sea bed occurs under wave motion. In this study, the mechanism of a disaster caused by the dynamic behavior of wave-structure interaction such as a floatation of a buried submarine pipeline, a flow out of back-filling sand behind a revetment and so on is investigated experimentally and theoretically.
1.A dynamic response of submarine pipeline buried in a sandy seabed under cyclic loading of water pressure is examined experimentally and theoretically. Characteristics of cyclic hydrodynamic forces acting on the buried pipeline is clarified by small scale laboratory tests, and a floatation process of the buried pipeline is also clarified by the method of discreet element analysis. A parametric study was carried out in order to investigate the influence of burial depth, specific weight of pipeline, permeability of sand bed, and frequency of pressure loading on the floatation of pipe. An analysis of the pipeline stability potential against floatation is presented, in which all the experimental test cases are verified.
2.A dynamic behavior of sand bed around revetment under cyclic loading of water pressure is investigated experimentally and theoretically. Flow out of back-filling sand is confirmed experimentally. Validity of the high permeable sand and the length of the revetment to reduce the amount of flow out of back-filling sand is clarified.
3.Flow out process of back-filling sand behind revetment is simulated by coupled analysis of distinct element method and finite element method. DEM-FEM analysis showed the flow out process of back-filling sand behind revetment under wave motion.
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