Applicable one-dimensional frozen method for obtaining undisturbed natural sand material containing fine particles

适用于获得含细颗粒原状天然砂料的一维冷冻方法

• 批准号: 11555127
• 负责人: YASHIMA Atsushi
• 金额: $ 4.22万
• 依托单位: Gifu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B).
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11555127/
• 关键词: 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

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.

为了评估桑迪地基的液化潜力和设计防止土壤液化的对策，有必要对未受扰动的天然砂样品进行实验室试验。有时在现场取砂之前使用地面冻结技术。然而，众所周知，这种技术非常昂贵。另一方面，管道取样技术比地面冻结技术便宜得多。为提高管取样技术所取砂样的质量，对取心管进行了重新设计，并在取心管前用防冻液对砂粒和地下水进行了固化处理。在大坂岸和田市填海造地试验了该取样技术，并对该技术回收的原状土样进行了大直径试件的三轴压缩试验。将实验结果与重构样品的结果进行了比较。研究亦在赤洲和六高岛进行砂土和黏土取样，比较两个填海岛屿的液化潜力。通过室内原状土样试验，研究了粘土的循环强度和固结历史。还在两个岛上进行了PS loasting。根据实验室和现场调查，解释了1995年兵库县南部地震中两岛液化灾害的差异。

项目成果

岡二三生: "砂の細粒分組成と液状化の抵抗の関係について"液状化メカニズム・予測法と設計法に関するシンポジウム発表論文集. 1. 419-424 (1999)

Fumi Oka：“砂的细粒成分与液化阻力之间的关系”液化机制、预测方法和设计方法研讨会论文集 1. 419-424 (1999)。

Fusao Oka: "Time dependent ground motion amplification at reclaimed land after the 1995 Hyogo-ken-nanbu earthquake"Proc.12WCEE. 2046 (2000)

Fusao Oka：“1995 年兵库县南部地震后开垦土地上随时间变化的地面运动放大”Proc.12WCEE。

Oka, F., Sugito, M., Yashima, A., Furumoto, Y.and Yamada, K.: "Time dependent ground motion amplification at reclaimed land after the 1995 Hyogo-ken-nanbu earthquake"Proc.12WCEE. (CD-ROM)2046. (2000)

Oka, F.、Sugito, M.、Yashima, A.、Furumoto, Y. 和 Yamada, K.：“1995 年兵库县南布地震后填海地区随时间变化的地面运动放大”Proc.12WCEE。

Fusao Oka: "Time dependent ground motion amplification at reclaimed land after the 1995 Hyago-ken-Nanbz earthquak"Proc. 12WCEE. CD. 2046 (2000)

Fusao Oka：“1995 年 Hyago-ken-Nanbz 地震后开垦土地上随时间变化的地面运动放大”Proc。

Sugito, M., Oka, F., Yashima, A., Furumoto, Y.and Yamada, K.: "Time-depenground motion amplification characteristics at reclaimed land after the 1995 Hyogoken Nambu Earthquake"Engineering Geology. 56. 137-150 (2000)

Sugito, M.、Oka, F.、Yashima, A.、Furumoto, Y. 和 Yamada, K.：“1995 年兵库县南部地震后填海区的时间相关运动放大特性”工程地质。