| Project/Area Number |
11555127
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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 | 展開研究 |
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| Research Field |
Geotechnical engineering
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| Research Institution | Gifu University |
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Principal Investigator |
YASHIMA Atsushi Gigu University, Department of Civil Engineering, Professor, 工学部, 教授 (90144394)
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| Co-Investigator(Kenkyū-buntansha) |
MIMURA Mamoru Kyoto University, Disaster Prevention Research Institute, Associate Professor, 防災研究所, 助教授 (00166109)
ZHANG Feng Gifu University, Department of Civil Engineering, Associate Professor, 工学部, 助教授 (70303691)
OKA Fusao Kyoto University, Department of Civil Engineering, Professor, 大学院・工学研究科, 教授 (10111923)
OKAMURA Mitsu Public Works Research Institute, Senior Researcher, 土木研究所, 主任研究員
TANAKA Hiroyuki Port Habour Research Institute, Chief, 港湾空港研究所, 室長
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1999: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Keywords | sand sampling / liquefaction / reclaimed land / consolidation / freezing method / SEM / undisturbed sample / Aluvial clav / 自然砂 / 細粒分 / 凍結 / 三軸圧縮試験 / 変形係数 / 埋立地 / サンプリング / 砂 / X線回折 / 一次元凍結 / ラバルサンプラー |
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| Research Abstract |
Laboratory tests on undisturbed natural sand samples are necessary to assess the liquefaction potential of the sandy ground and to design countermeasures against soil liquefaction. The ground freezing technique has been sometimes used before sand sampling at the field. This technique is, however, well known to be very expensive. On the other hand, the tube sampling technique is much cheaper then the ground freezing technique. The quality of the sample retrieved by the tube sampling technique has been, however, found to be lower than that by the ground freezing technique.
In this study, to improve the quality of the sand sample by the tube sampling technique, the coring tube was redesigned and antifreeze liquid was used to solidify the sand particles and ground water before retrieving the coring tube. The proposed sampling technique was tried at the reclaimed ground in Kishiwada city, Osaka.
Triaxial compression tests on undisturbed samples retrieved by the proposed technique were carried out using large diameter specimens. The experimental results were compared with those obtained from the reconstituted specimens. It is found that the undisturbed specimen has higher stiffness than the reconstituted specimen.
Sand and clay samplings were also conducted at Port Island and Rokko Island to compare the liquefaction potential of both reclaimed islands. Laboratory tests on undisturbed clayey samples were carried out to investigate cyclic strength of clay and consolidation history. PS loggings were also conducted at both islands. Based on laboratory and in situ investigations, the difference in the liquefaction disaster appeared on both islands during the 1995 Hyogoken-Nambu Earthquake was explained.
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