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.

有必要对原状天然砂样品进行实验室测试，以评估沙地的液化潜力并设计土壤液化对策。有时在现场进行沙样取样之前会使用地面冻结技术。然而，众所周知，该技术非常昂贵。另一方面，管采样技术比地面冷冻技术便宜得多。然而，通过管取样技术取回的样品质量被发现低于地面冷冻技术。在本研究中，为了提高管取样技术所取沙样的质量，取芯管在收回取芯管之前，使用重新设计的防冻液来固化沙粒和地下水。所提出的采样技术在大阪岸和田市的填海区进行了试验。使用大直径样本对通过所提出的技术回收的原状样本进行了三轴压缩试验。将实验结果与从重构样本中获得的结果进行比较。结果发现，原状样本比重建样本具有更高的刚度。还在港口岛和六甲岛进行了沙子和粘土采样，以比较两个填海岛屿的液化潜力。对原状粘土样品进行了实验室测试，以研究粘土的循环强度和固结历史。两个岛屿也进行了 PS 伐木。基于实验室和现场调查，解释了1995年兵库县南部地震期间两岛出现的液化灾害的差异。

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。