| Project/Area Number |
20K04681
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 22030:Geotechnical engineering-related
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| Research Institution | Research Institute of Shimizu Construction Co. (2021-2022)
Nagaoka University of Technology (2020) |
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Principal Investigator |
Chen Jian 清水建設株式会社技術研究所, その他部局等, 研究員 (30556668)
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| Co-Investigator(Kenkyū-buntansha) |
杉本 光隆 長岡技術科学大学, 工学研究科, 教授 (50196755)
豊田 浩史 長岡技術科学大学, 工学研究科, 教授 (90272864)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2020: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
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| Keywords | 連成解析 / 土壌凍結特性曲線 / 水遷移 / パラメータ同定 / 不凍水分量 / ワイブル分布 / 圧力溶解 / 潜熱効果 / 凍結特性曲線 / 凍土造成 / 不飽和透水係数 / 熱伝導 / 凍土 / 不凍水量 |
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| Outline of Research at the Start |
本研究は，核磁気共鳴実験で明らかになってきた土中の氷と水の相転移特性を，水分質量保存則のシンク（Sink）とソース（Source）項に付与し，凍結融解に伴う土の強度・剛性の変化や不凍水量のヒステリシスを記述できる構成式を導入し，凍結融解作用を受ける地盤の変位挙動をより正確に予測する手法を開発することが主な特徴である。
本研究により，寒冷地にある自然斜面や人工斜面の融雪期の地すべり危険度の評価，災害予測，また，地盤凍結工法において解凍沈下による近接インフラ構造物への影響評価が可能となる。
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| Outline of Final Research Achievements |
The hysteresis phenomenon of the unfrozen water content occurs because the ice content and hydraulic conductivity change greatly due to the freezing-thawing process of soils. It is necessary to develop a heat-water-stress coupled analysis model that can consider such a complicated moisture history.
Based on the porous media theory, this study considers the phase transition characteristics of ice and water in soils, which have been clarified by nuclear magnetic resonance experiments. The phase transition characteristics were represented as soil freezing characteristic curve into the proposed model. A more versatile heat-water-stress coupled model was constructed.In addition, soil column freezing experiments with and without water supplying were conducted. The experimental and the simulated results of temperature, water content, and frost heave were compared to verify the proposed model. The effects of moisture, heat transfer and deformation properties during freezing were clarified.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では，複雑な水分履歴を考慮できる熱-水-応力連成解析モデルの構築と検証を目的として，主に理論モデルの定式化，土のカラム凍結実験および連成解析結果の検証，を実施した．
本研究結果は，より実現象を反映する連成モデルの構築を実現するもので，自然地盤の凍上や人工凍結工法による地盤変形に関する予測精度の向上，ひいては，地盤災害の軽減に寄与すると考えられる．
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