Applicability of chemical grouting for the improvement of liquefaction susceptibility of saturated sandy deposits

化学注浆在改善饱和砂质沉积物液化敏感性中的应用

• 批准号: 13650547
• 负责人: TOBITA Yoshio
• 金额: $ 2.24万
• 依托单位: Tohoku Gakuin University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650547/
• 关键词: chemical grouting; injection; liquefaction; seepage failure; constitutive model; homogenization; cyclic triaxial test; dilatancy; セメント溶液; 繰り返し3軸; 有限要素法; 薬液注入; 混合体

The fact that sandy deposits treated by chemical grouting show good resistance to liquefaction during strong earthquakes is well known. The fundamental mechanisms leading to resistant behavior remain unknown up to the present time. In order to get insight into the mechanisms, several experimental works have been performed in this research project. In particular, the increase of resistance to liquefaction treated by a low-content silica was investigated in detail, which leads to the improvement of sandy deposits with reasonable costs. The application of chemical grouting for the purpose of the improvement of sandy deposits to practice requires the numerical analyses on the distribution of grouting and strength. For the proper analysis of the problem requires the well behaved constitutive model with account for the effect of dilatancy and increase of strength. In addition to chemical grouting, cement paste was used as an alternative material leading to the increase of the resistance to l … More iquefaction. The main results obtained through this study can be summarized as follows :1.Cyclic triaxial tests were performed on the specimen with varying the contents of silica. The specimens with the contents more than 3% show the change in dilatancy with the tendency of expansion, which is believed to result in the resistant behavior to liquefaction;2.The specimens with the content less than 3% show little difference in strength and dilatancy behavior, although shear deformation shows a little increase after initial liquefaction (pore water pressure reaches to the initial effective confining pressure), which reduces the possibility of complete (catastrophic) liquefaction. This fact may indicate the fact that low hydraulic conductivity of treated specimen with low content of silica prevents the specimen from showing catastrophic liquefaction failure, which is partly supported by the quick sand test with the result that the treated sand shows high resistance to quick sand and needs a long duration until final failure occurs.3.In addition to chemical grouting, the cement paste which leads to the higher strength were used as a material for improving sand deposits. For the purpose of injecting the liquid with high viscosity, the method with varying the injection speed was found effective.4.To understand the overall mechanical behavior of treated sand with silica and cement, the homogenization technique was applied to bridge the micromechanical behavior and macroscopic behavior. More study is required to apply the method to the complex material.5.The severe damages due to liquefaction are believed to occur with the flow of sandy deposits during and after strong earthquake excitation. The constitutive model was developed in order to account for the effects of change in density of sand and was applied to the problem of flow due to the movement of pore water.These results were fully discussed in the research report (in Japanese). Less

众所周知，经过化学灌浆处理的砂质沉积物在强震期间表现出良好的抗液化能力。迄今为止，导致抵抗行为的基本机制仍然未知。为了深入了解其机制，该研究项目进行了多项实验工作。特别是，详细研究了低含量二氧化硅处理后抗液化能力的提高，从而以合理的成本改善了砂质沉积物。将化学注浆用于改善砂质沉积物的实际应用需要对注浆和强度的分布进行数值分析。为了正确分析问题，需要性能良好的本构模型，并考虑剪胀和强度增加的影响。除了化学灌浆外，还使用水泥浆作为替代材料，从而提高了抗液化能力。本研究取得的主要结果可概括如下： 1.对不同二氧化硅含量的试件进行了循环三轴试验。含量大于3%的试件表现出剪胀性的变化并有膨胀的趋势，这被认为是抗液化行为的原因；2.含量小于3%的试件在强度和剪胀性方面差异不大，但在初始液化后（孔隙水压力达到初始有效围压）剪切变形略有增加，降低了完全（灾难性）的可能性。 液化。这一事实可能表明，经过处理的低硅含量试件的低水力传导率可以防止试件出现灾难性的液化破坏，这在一定程度上得到了流砂试验的支持，结果是处理过的砂对流砂表现出很高的抵抗力，并且需要很长时间才能发生最终破坏。 3.除了化学灌浆之外，还使用了导致更高强度的水泥浆作为改善砂沉积的材料。对于注入高粘度液体的目的，改变注入速度的方法是有效的。4.为了了解二氧化硅和水泥处理砂的整体力学行为，应用均化技术来连接微观力学行为和宏观行为。需要更多的研究将该方法应用于复杂材料。5.据认为，强震期间和之后砂质沉积物的流动会导致液化造成的严重破坏。开发本构模型是为了考虑沙子密度变化的影响，并将其应用于由于孔隙水运动引起的流动问题。这些结果在研究报告（日文）中进行了充分讨论。较少的

项目成果

繰り返し三軸試験機を用いた低濃度薬液改良砂の改良メカニズムの検討

重复三轴试验机研究低浓度化学溶液改性砂的改良机理

• 发表时间: 2003
• 期刊: 土木学会東北支部技術研究発表会講演概要 (口頭発表)
• 作者: 田口 真;高田;飛田;山口
• 通讯作者: 山口

山口晶, 仙頭紀明, 風間基樹, 飛田善雄: "原位置試料を用いた埋立人工島のハイブリッド地震応答実験"第11回日本地震工学シンポジウム論文集(口頭発表). 791-796 (2002)

Akira Yamaguchi、Noriaki Senzu、Motoki Kazama、Yoshio Tobita：“使用原位样本的填海人工岛混合地震响应实验”第 11 届日本地震工程学会论文集（口头报告）791-796（2002 年）。

Influence of strength of clay layer and reclaimed materials on the earth quake behavior of reclaimed land

粘土层及复垦材料强度对复垦地地震行为的影响

• 发表时间: 2002
• 期刊: Annual report of Faculty of Engineering, Tohoku-Gakuin University 37,1(in Japanese)
• 作者: Akira Ymaguchi;Yoshio Tobita;Hideo Nitta;Kouji Nitoh
• 通讯作者: Kouji Nitoh

相原光貴, 山口晶: "初期せん断を有する地盤の地震中及び地震後に発生する流動変形に関する研究"土木学会東北支部技術研究発表会講演概要(口頭発表). 392-393 (2003)

相原光隆、山口晃：“研究地震发生时和地震后发生初始剪切的流动变形”日本土木工程学会东北分会技术研究会议上的演讲摘要（口头演讲） . 392-393 (2003)

原位置試料を用いた埋立人工島のハイブリッド地震応答実験

填海人工岛原位样品混合地震响应试验

• 发表时间: 2002
• 期刊: 第11回日本地震工学シンポジウム論文集 (口頭発表)
• 作者: 山口晶;仙頭紀明;風間基樹;飛田善雄
• 通讯作者: 飛田善雄