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

地震脂肪作用引起的侧向扩散会导致地面经历较大的位移和剪切菌株，进而损坏了由于阻力而造成的桩基础。模拟这个问题有两个困难。评估液化土壤的本构模型以及适合如此大变形问题的适当模拟工具的选择。这项研究的目的是从微机械的角度找到解决这些困难的方法。首先，我们使用高速摄像头和PIV开发了一些实验技术（粒子图像速度计）。 PIV是一种强大的工具，可检测从顺序数字图像的各种实验的速度场。我们进行了两种类型的实验：一种是对Toyoura砂的震动表测试，以观察小型地面模型的表面，另一种是一种渗透性测试，可通过从样品底部调整液体注入速度来保持任意液化状态。在这两种经验中……更多的NTS，由于样品和管道之间的相对位移，安装了圆柱管以测量作用在其上的阻力。发现液化的土壤具有固体的特性（通过土壤和桩之间的棒滑动运动检测）和粘性液（以速率依赖性响应为特征）。通过DEM进行研究（离散元素方法）。 DEM是一种基于牛顿的第二项运动定律计算每种固体晶粒的模拟方法，并且晶粒之间的相互作用简单地通过弹簧式式刀具系统建模。一系列恒定体积的简单剪切模拟为我们提供了在LipeFaction之前和之后观察基本的微型机制。 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 lipefaction.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可以在固体和流体中应用。发现包括重新溶解度的桩层土壤相互作用通过SPH成功模拟。较少的

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）。

ボイリング時における粒子-流体系内部の可視化と速度場計測

沸腾过程中颗粒-流体系统内部的可视化和速度场测量

• 发表时间: 2004
• 期刊: 第39回地盤工学研究発表会講演概要集
• 作者: Naili;M.;Matsushima;T.;Yamada;Y.;Takashi Matushima;Mounir NAILI;竿本英貴;Mounir NAM;竿本英貴;Mounir NAILI;Mounir NAILI;竿本英貴;Mounir NAILI;松島亘志;竿本英貴
• 通讯作者: 竿本英貴