2018 Fiscal Year Final Research Report
Evaluation of factors of deformation behavior of sand during methane hydrate production by discrete element method
| Project/Area Number |
17H06899
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Single-year Grants |
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| Research Field |
Geotechnical engineering
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| Research Institution | Yamaguchi University |
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Principal Investigator |
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| Project Period (FY) |
2017-08-25 – 2019-03-31
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| Keywords | メタンハイドレート / 個別要素法 |
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| Outline of Final Research Achievements |
The deformation behavior during dissociation of methane hydrate bearing sand (MH bearing sand) was evaluated experimentally and analytically.
Analytically, it was possible to reproduce samples with high MH saturation with low computational complexity. The analysis was performed using this model. It was clear that in the isotropic consolidation state, the volumetric strain due to the MH particle elimination accompanied by the increase of the effective stress is larger than that in the case where only the MH particle is eliminated.
From the results of the isotropic compression test, it became clear that under a constant effective stress, there was time dependency of the increment of the void ratio to become large with the passage of a certain time. A longer time was required to increase the increment of the void ratio than that of the host sand and the increment of the void ratio tended to be larger in the MH bearing sand than that of host sand.
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| Free Research Field |
地盤工学
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| Academic Significance and Societal Importance of the Research Achievements |
メタンハイドレート(以下，MH)の生産中の地盤は，土，水，MH，ガスが複雑に混在しており，安全にMHを生産するには地盤の挙動を把握することが重要である．このために，様々な生産シミュレーションが行われているが，先述の通り生産中の地盤の挙動は学術的に多分野に亘っているため，シミュレーションの開発元によって異なる特色があるものが存在している．本研究では，変形挙動に着目し，その要因をいくつかに分割し，要因ごとの変形の程度を把握し，変形要因の優先順位を与えることで，生産シミュレーションを行う際に工学的意味のある範囲で要因ごとに分析する重要性，重み付けが出来る可能性を示した．
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