Micromechanics Study on Liquefaction-Induced Lateral Flow and Soil-Pile Interaction

液化诱发侧流及土-桩相互作用的微观力学研究

• 批准号: 15360249
• 负责人: YAMADA Yasuo
• 金额: $ 9.41万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360249/
• 关键词: Liquefaction; Lateral ground flow; Visualization technique; PIV (particle image Velocimetry); LAT (Laser-Aided tomography); DEM (Discrete Element Method); SPH (Smoothed Particle Hydrodynamics); Micromechanics; 杭基礎; 微視力学; 構成則; 流動; 個別要素法

Lateral spreading induced by seismic liquefaction causes the ground to experience large displacement and shear strains, which in turn damage pile foundations due to the drag force. There are two difficulties in simulating this problem ; the evaluation of constitutive model for liquefied soil and the choice of adequate simulation tool suitable for such large deformation problem. The objective of this study is to find a way for these difficulties from a micromechanical standpoint.Firstly, we developed some experimental techniques using high-speed camera and PIV (Particle Image Velocimetry). PIV is a powerful tool to detect a velocity field of various experiments from sequential digital images. We performed two types of experiments : one is a shaking table test of Toyoura sand to observe a surface of small-sized ground model, and the other is a kind of permeability test to keep arbitrary liquefaction state by tuning a fluid injection speed from the bottom of the specimen. In both experime … More nts, a cylindrical pipe is installed to measure the drag force acting on it due to the relative displacement between the specimen and the pipe. It was found that the liquefied soil has both properties as a solid (detected by a stick-slip motion between the soil and the pile) and as a viscous fluid (characterized by the rate dependent response).Further investigation was made by DEM (Discrete Element Method). DEM is a simulation method to compute each solid grains based on Newton's second law of motion, and the interaction between grains is simply modeled by a spring-dashpot-slider system. A series of constant-volume simple shear simulations provided us to observe essential micro-mechanisms up to and after liquefaction. In particular, the re-solidification of liquefied soil was also successfully simulated, which is quite important factor to predict the lateral flow displacement due to liquefaction.Based on the above information, we proposed a constitutive model of granular assembly based on micromechanics, which can be well applied up to shear failure of the assembly.Finally, we studied SPH (Smoothed Particle Hydrodynamics), a particle-based simulation method for continuum, which can be applied both in solid and fluid. It was found that the pile-liquefied soil interaction including the re-solidification regime was successfully simulated by SPH. Less

由地震液化引起的侧向扩展导致地面经历大的位移和剪切应变，这反过来又由于拖曳力而损坏桩基。液化土的本构模型的评价和适用于液化土大变形问题的模拟工具的选择是模拟液化土大变形问题的两个难点。本研究的目的就是从微观力学的角度来解决这些问题。首先，我们利用高速摄像机和粒子图像测速仪（PIV）发展了一些实验技术。PIV是从序列数字图像中检测各种实验的速度场的有力工具。我们进行了两种类型的实验：一种是丰浦砂的振动台试验，以观察小型地面模型的表面，另一种是渗透性试验，以保持任意的液化状态，通过调整流体注射速度从底部的标本。在两个实验中， ...更多信息 nts，安装圆柱形管以测量由于试样和管之间的相对位移而作用在其上的拖曳力。结果表明，液化土既具有固体特性（通过土与桩之间的粘滑运动来检测），又具有粘性流体特性（通过速率相关响应来表征）。离散元法是一种基于牛顿第二运动定律计算固体颗粒的模拟方法，颗粒间的相互作用被简化为弹簧-阻尼器-滑块系统。一系列的定容简单剪切模拟为我们提供了必要的微观机制，液化和液化后。在此基础上，提出了一种基于细观力学的颗粒集合体本构模型，该模型能够很好地应用于颗粒集合体的剪切破坏，并对SPH进行了研究光滑粒子流体动力学（Smoothed Particle Hydrodynamics）是一种基于粒子的连续介质模拟方法，可应用于固体和流体。研究结果表明，SPH方法能够成功地模拟桩-液化土相互作用过程，包括再固化过程。少

项目成果

A 2D Smoothed Particle Hydrodynamics method for liquefaction induced lateral spreading analysis

• DOI: 10.2208/journalam.8.591
• 发表时间: 2005-08
• 期刊: Journal of Applied Mechanics
• 作者: M. Naili;T. Matsushima;Yasuo Yamada

LAT-PIV Visualization technique and Application to solid particle-fluid interaction

LAT-PIV可视化技术及其在固粒-流体相互作用中的应用

• 发表时间: 2005
• 期刊: Journal of Applied Mechanics, JSCE (in Japanese) Vol.8
• 作者: Hidetaka Saomoto;Takashi Matsushima;Yasuo Yamada
• 通讯作者: Yasuo Yamada

SPH-DEM手法の開発とボイリング現象への適用

SPH-DEM方法的发展及其在沸腾现象中的应用

• 发表时间: 2005
• 期刊: 第40回地盤工学研究発表会講演概要集 (CD-ROM)
• 作者: Naili;M.;Matsushima;T.;Yamada;Y.;Takashi Matushima;Mounir NAILI;竿本英貴;Mounir NAM;竿本英貴
• 通讯作者: 竿本英貴

竿本 英貴: "デジタル画像を利用した粒子-流体系内部の速度場計測"土木学会第58回年次学術講演会. (2003)

Hidetaka Kanomoto：“使用数字图像测量粒子流体系统内的速度场”第 58 届日本土木工程师学会学术年会（2003 年）。

An elasto-plastic constitutive model of granular materials based on contact force distribution,

基于接触力分布的颗粒材料弹塑性本构模型，

• 发表时间: 2006
• 期刊: IS-Yamagushi (International Symposium on Geomechanics and Geotechnics of Particulate Media)
• 作者: Matsushima;T.;Chang;C.-S.
• 通讯作者: C.-S.