2005 Fiscal Year Final Research Report Summary
A long-term delayed consolidation settlement of naturally deposited soil and its prediction and improvement methods
| Project/Area Number |
16360236
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Nagoya University |
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Principal Investigator |
ASAOKA Akira Nagoya University, Engineering, Professor, 大学院・工学研究科, 教授 (50093175)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANO Masaki Nagoya University, Engineering, Associate Professor, 大学院・工学研究科, 助教授 (00252263)
NODA Toshihiro Nagoya University, Engineering, Associate Professor, 大学院・工学研究科, 助教授 (80262872)
YAMADA Eiji Nagoya University, Engineering, Assistant Professor, 大学院・工学研究科, 助手 (00293647)
NAKAI Kentaro Nagoya University, Engineering, Assistant Professor, 大学院・工学研究科, 助手 (60402484)
TASHIRO Mutsumi Nagoya University, Graduate School of Environmental Studies, Research Associate, 大学院・環境学研究科, 研究員 (00422759)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Clay / Soli structure / Consolidation / Overconsolidation / Anisotropy / Elasto-plastic constitutive equation |
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| Research Abstract |
In a naturally deposited clay foundation subject to embankment loading, a delayed settlement can often be observed after the embankment's completion, sometimes also showing acceleration over time. The settlement cannot be always predicted from the laboratory test results even with the undisturbed sample. The prediction of the settlement and the long-term period were always underestimated.
In the present study, the compression index ratio Cd Ccr was defined by the ratio of the compression index of the undisturbed sample Cc to remolded sample Ccr, and the in-situ settlement data and the laboratory test results on the about 50 expressways are estimated and classified by the compression index ratio Cd Ccr and sensitivity index St. The mechanism of the large delayed settlement is discussed described by using a soil-water coupled finite deformation analysis with the Supre/subloading Yield Surface Cam-clay model (SYS Cam-clay model). The new findings are as follows :
1)The clay, which exhibits a long-term large settlement beyond the prediction, can have high sensitivity St, the value of which is more than 8.0 and high the compression index ratio Cd Ccr, more than 1.5. Through the simulation by the SYS Cam-clay model, the clay is a high degree of initial structure and show fast decay of the structure.
2)The in-situ compression behavior was predicted from the laboratory test assuming that both the consolidation yield stresses are the same, and the mechanism of the long-term large settlement was discussed taking the sample disturbance into consideration.
3)The occurrence of in-situ secondary/delayed consolidation of clay foundation in Nagashima can be described by using a soil-water coupled finite deformation analysis with the SYS Cam-clay model, and it provide that it is necessary to determine the in-situ initial condition from the laboratory test taking the sample disturbance into consideration.
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[Journal Article] Estimation of in-situ conditions of clay soil and simulation of delayed consolidation settlement considering sampling disturbance.2006
Author(s)
Tashiro, M., Noda, T., Nakano, M., Asaoka, A., Inagaki, M., Ohinata, Y.
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Journal Title
Proceeding of 41th JGS (The Japanese geotechnical society) annual meeting (in printing)
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Interpretation of mechanical behavior of naturally deposited clay with different degree of soil skeleton structure based on elasto-plastic mechanics.2005
Author(s)
Nakano, M., Noda, T., Asaoka, A., Nakai, K., Tashiro., M., Inagaki., M.
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Journal Title
Proceeding of 40th JGS (The Japanese geotechnical society) annual meeting
Pages: 993-994
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Factors of progressive consolidation settlement of highly structured clayey soil.2005
Author(s)
Noda, T., Nakano, M., Asaoka, A, Tashiro, M., Inagaki, M., Ishida, Y.
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Journal Title
Proceeding of 40th JGS (The Japanese geotechnical society) annual meeting
Pages: 995-996
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Long-term continuous settlement with progressive failure of soil skeleton structure.2005
Author(s)
Noda, T., Nakano, M., Asaoka, A., Tashiro, M., Inagaki, M., Ishida, Y.
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Journal Title
Proceeding of 40th JGS (The Japanese geotechnical society) annual meeting
Pages: 997-998
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Interpretation of mechanical behavior of marine clay with the occurrence of long-term settlement based on the evolution of soil-skeleton structure.2004
Author(s)
Nakano, M., Asaoka, A., Noda, T., Nakai, K., Niwa, S., Hosono, S., Sibahara, T., Inagaki, M.
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Journal Title
Proceeding of Chubu JSCE annual meeting
Pages: 269-270
Description
「研究成果報告書概要(欧文)」より
