THE EARTHQUAKE-RESISTANT REINFORCEMENT OF PILE FOUNDATIONS WITH DIAPHRAGM WALL TO LATERAL FLOW OF LIQUEFIED GROUND

连续墙桩基对液化地层侧流的抗震加固

• 批准号: 11650493
• 负责人: KATADA Toshiyuki
• 金额: $ 2.3万
• 依托单位: Musashi Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 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/grant/KAKENHI-PROJECT-11650493/
• 关键词: Pile Foundations; Liquefaction; Lateral Spreading; Diaphragm Walls; Reinforcement; Centrifuge Modeling Test; Laminated Container; せん断変形; 既設杭基礎; Pile Foundations; Liquefaction; Lateral Spreading; Diaphragm Walls; Reinforcement; Centrifuge Modeling Test; Laminated Container; せん断変形; 既設杭基礎

According to the centrifugal model experiment carried out in this study, the bending moment of the pile decreased to about the half by the reinforcement of the diaphragm wall. This reinforcing mechanism was clarified by the experiment on this year as follows. The pressure area of the diaphragm wall was bigger than that of the piles. Therefore, the flow pressure of the liquefied sand that affected the diaphragm wall was bigger than that of the piles. Next, the bending moment of the piles decreased by reinforcement of diaphragm wall because the bending rigidity of diaphragm wall is considerably bigger than that of the piles. The diaphragm wall moves as rigid body and the piles move as a cantilever beam of which the tip was fixed, when the liquefied sandy ground flows. This shows that the diaphragm wall must be installed to the sufficient depth of the non-liquefaction layer. The sufficient installation generated the horizontal resistance force of the diaphragm wall by the bearing capacity of the ground. And then, the flow pressure and the bending moment in the piles decreased. But if the range of the liquefaction spreads to the bottom of the diaphragm wall and the bearing capacity of the ground disappears, the diaphragm wall loses the resistance force for lateral flow. As the result, the diaphragm wall flows and large force affects the piles. This generated the large bending moment at the pilesThe conclusions of this research are as follows ; it is important to install the diaphragm wall to the sufficient depth to the non-liquefaction layer, though the reinforcement of pile foundation by the diaphragm wall is the sufficient effect for lateral flow.

根据这项研究中进行的离心模型实验，桩的弯曲力矩通过膜片壁的加固降至一半。今年的实验阐明了这种加强机制，如下所示。隔膜壁的压力面积大于桩的压力区域。因此，影响隔膜壁的液化砂的流动压力大于桩的流动压力。接下来，由于隔膜壁的弯曲刚度比桩的弯曲刚度大得多，因此桩的弯矩降低了。隔膜壁作为刚体的身体移动，而桩作为悬臂梁移动，当液化的沙质地面流动时，尖端的尖端是固定的。这表明必须将隔膜壁安装到非亮凹层的足够深度上。足够的安装通过地面的轴承能力产生了隔膜壁的水平电阻力。然后，桩中的流动压力和弯矩减少。但是，如果液化的范围扩散到隔膜壁的底部并且地面的轴承能力消失，则隔膜壁将失去侧向流动的电阻力。结果，隔膜壁流动和大力会影响桩。这在这项研究的Pilesthe结论中产生了巨大的弯曲时刻如下；将隔膜壁安装到足够的深度至非浅色膨胀层非常重要，尽管隔膜壁的桩基础的加固是横向流动的足够效果。