2021 Fiscal Year Final Research Report
Crushing characteristics of soil particles under high pressure stress paths
Project/Area Number |
19K04690
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 23010:Building structures and materials-related
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Research Institution | Hiroshima University |
Principal Investigator |
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Project Period (FY) |
2019-04-01 – 2022-03-31
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Keywords | 粒子破砕 / せん断強度 / 三主応力制御型高圧圧縮試験機 / 応力経路 / 平均応力 / 偏差応力 / 粒子破砕量 / 杭先端支持力 |
Outline of Final Research Achievements |
In practice, it may be important that the behavior of volume shrinkage and decreasing of shear strength due to particle crushing around pile tip in crushable sandy soils. The particle crushing of sandy soils are reasons of the rapid increasing of settlements and the decreasing of pile tip bearing capacity. This study focused on the particle crushing of sandy soils; further, a series of particle-crushing experiments of Toyoura silica sand was conducted using high-compression apparatus. First, the volumetric and deviatoric strains obtained in the particle-crushing experiments were divided into plastic and elastic components. Then, an approximation regression formula containing mean stress p and deviatoric stress q was defined to obtain the value of each component. These incremental approximation regression formulas are useful as non-linear constitutive relations in the numerical analysis of soil in consideration of particle crushing.
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Free Research Field |
地盤・基礎工学
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Academic Significance and Societal Importance of the Research Achievements |
土粒子の集合体である地盤の破壊現象の解析では、通常モール・クーロンの破壊規準を用いて定式化されている。ただし、高圧拘束下での土粒子には破砕現象が生じるため、容易に拡張できないことは自明である。本研究の学術的意義は、高圧拘束下における地盤の変形強度特性を表す構成関係を土粒子の破砕現象そのものを基に構築しようとするもので、高圧拘束下における土粒子の破砕に伴う地盤の体積収縮傾向や土粒子の微細化に伴う内部摩擦角の急激な減少傾向が定量的に説明できるようになる。高圧拘束下の粒子破砕現象を考慮した地盤の変形や破壊現象が合理的に推定できるようになれば、より安全で合理的な設計根拠となる点に社会的な意義がある。
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