2004 Fiscal Year Final Research Report Summary
Design procedures for embedded structure considering seabed gonging of deformed sea ice
| Project/Area Number |
15360259
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | HOKKAIDO UNIVERSITY |
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Principal Investigator |
SAEKI Hiroshi Hokkaido Univ., Grad.School of Eng., Prof., 大学院・工学研究科, 教授 (30001209)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yasunori Hokkaido Univ., Grad.School of Eng., Inst., 大学院・工学研究科, 助手 (20292055)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Pipeline / Sea ice / Scour / Gouge / Scale effect / Sub-scour deformation / Stress within seabed / Burial depth / Probability of failure |
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| Research Abstract |
We developed a simulation method of Ice Scour Event considering probability distributions of various environmental parameters. As a result of calculations made under various conditions, order similar to those in the field observation data -the scour length of several tens of meters to several kilometers and the scour depth of several tens of centimeters to several meters -were found. Furthermore, due to the similarity to (reproducibility of) the comprehensive tendency/property of actual scour events, results that compared favorably with field observation results were obtained. Using the simulation results we then can estimate the probability of failure of structures (probability of contact between structure and ice keel) according to burial depth. From the basis, we finally proposed an estimation method of optimal burial depth of seabed structures such as pipeline against ice scour event. It can be presumed that the above concept is based on a reliability design through which safety assessment for the case in which uncertainties surrounding the environment are prominent is possible.
Also, we made a medium-scale model experiment as well as the small-scale experiment in the last year related to "sub-scour deformation", which means stress transmission or soil deformation within the seabed below the sea ice. From the small-and medium scale model test results, we clarified the scale effects/similarities related to reaction forces and stress distributions within seabed While we made a simple pipeline-response analysis model due to the stress within seabed, we confirmed that calculation results by the model were almost corresponded to measured results. Using this method, we can calculate pipeline-response considering the scale effects. We also attempted to estimate the optimal burial depth of a pipeline considering the sub-scour deformation in an actual sea area. As a result, we found that it would be enough to bury a pipeline at 1.6 times deep as the scour depth.
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Research Products
(13 results)
