2022 Fiscal Year Final Research Report
Liquefaction characteristics of soils with aging effects at a wide range of strain levels and development of its evaluation method
Project/Area Number |
20H02240
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Single-year Grants |
Section | 一般 |
Review Section |
Basic Section 22030:Geotechnical engineering-related
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Research Institution | The University of Tokyo |
Principal Investigator |
Kiyota Takashi 東京大学, 生産技術研究所, 准教授 (70431814)
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Co-Investigator(Kenkyū-buntansha) |
上田 恭平 京都大学, 防災研究所, 准教授 (60649490)
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Project Period (FY) |
2020-04-01 – 2023-03-31
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Keywords | 液状化 / 年代効果 / 土粒子構造 / セメンテーション / 大ひずみ / シミュレーション / 三軸試験 / 中空ねじり試験 |
Outline of Final Research Achievements |
This study showed a new method for estimating liquefaction resistance that can consider the influence of soil fabric and confirmed its high applicability in the field. However, the applicability of the method to volcanic soils and to soils with cementation is not clear. In this study, volcanic soils and reconstructed samples mixed with a small amount of cement to simulate cementation in natural conditions were used to investigate the relationship between their liquefaction resistance and deformation characteristics and Vs. The results showed that for volcanic soils, the liquefaction resistance could be estimated using the framework of the above method using the particle strength as an indicator. In addition, a method that can represent the large deformation behaviour of liquefied soils by numerical simulation was found in terms of the damage to the friction angle associated with liquefaction, and a simulation that considered this successfully reproduced the experimental results.
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Free Research Field |
地盤工学
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Academic Significance and Societal Importance of the Research Achievements |
本研究の成果により、従来その評価が困難であった液状化強度に及ぼす地盤の年代効果(土粒子構造の影響)の影響が定量的に可能となった。これにより、従来大幅に過小評価されていた液状化強度が適切に求められ、地盤耐震設計の合理化とコスト削減が期待できる。特に近年の大地震の経験を背景に、従来の設計地震荷重よりも著しく大きいレベル2地震動に対する設計も行われるようになってきた昨今、たとえ建設対象が重要構造物であれ、高額な費用をかけて地盤の液状化対策を実施することが妥当かどうかを判断することが求められているが、本研究成果はそのような検討に非常に有効である。
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