| Project/Area Number |
17H06613
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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 | The University of Tokyo |
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Principal Investigator |
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| Research Collaborator |
KUWANO reiko
O'Sullivan Catherine
Hanley Kevin J.
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| Project Period (FY) |
2017-08-25 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 地中空洞 / 地盤陥没 / アーチ効果 / 個別要素法 / 模型実験 / 粒状体 / 波動伝播 / 粒子間付着力 / 地盤工学 / 土質力学 / 数値解析 / アーチ機構 / 粒子形状 |
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| Outline of Final Research Achievements |
This study investigated the development/expansion of a subsurface cavity and the mechanism of subsequent sinkhole. Soils with dry or submerged conditions cannot sustain a subsurface cavity due to lack of inter-particle suction, which causes surface settlement. Similarly, soils comprised of poorly graded large grains cannot sustain a subsurface cavity as the suction force is insufficient even under unsaturated conditions. When a stable cavity is held due to arching effects, the surface settlement appears to be negligible. However, repetition of increase/decrease in underground water level induces growth of cavity followed by a catastrophic collapse of the ground surface. Using the discrete element method, for various median sizes of soil grains, the influence of degree of saturation and shape of soil grain (i.e. interlocking effects) on the stability of ground were analysed.
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| Academic Significance and Societal Importance of the Research Achievements |
学術的意義としては、本研究課題に関する縮小模型実験手法を確立させたこと、地中空洞安定性に及ぼす地盤材料の粒径、粒子形状、粒子表面摩擦、締固め密度の影響を検討したこと、新たな数値解析コードを用いて空洞周りのアーチ効果および飽和度の影響を粒子スケールで評価したこと、空洞を有する地盤の弾性波伝播特性を実験・数値解析にて検討したこと、などが挙げられる。
今後も基礎的研究を継続することで、地盤材料特性および飽和度データを有効活用した陥没危険度評価手法の高度化に貢献できる。また、地中空洞レーダーで計測可能な空洞形状の情報を基にした安定解析を実施することができ、現行の陥没危険度評価指針の一助となり得る。
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