Mathematical and Experimental Approaches for Evaluation of Dynamic and Static Stability of Granular Structures

上述六位研究人员为澄清粗粒材料的变形过程所做的所有努力都总结在这项研究的最终报告中。术语“粗”是指，与其边界的尺寸和合成树脂片的尺寸相比，颗粒具有相当大的代表性尺寸，不可忽视，例如，与颗粒混合以提高其强度。研究人员总共研究了10个主题，包括与颗粒结构有关的静态和动态问题，如人工和/或天然斜坡、铁路道碴、不同粒度分布的天然颗粒土沉积。由于颗粒之间没有或相对较弱结合的颗粒材料从来不像连续介质那样表现，因此研究人员还致力于开发可视化和模拟颗粒行为的新方法。LAT(激光辅助层析成像)是一种新的方法，它通过使用玻璃颗粒、与玻璃具有相同折射率的液体和强激光薄片来清楚地显示所有颗粒的形状和运动及其组合。用数值模拟方法DEM(离散单元法)研究了颗粒间的相互作用及其对颗粒整体行为的影响。

All atempts by the above six investigators to clarify deforming processes of coarse granular materials are summarized in the final report of this study.The terminology "coarse" means that grains have fairly large representative sizes that can not be ignored, when compared with dimensions of their boundaries and sizes of synthetic resin pieces, for example, that are mixed up with the grains to enhance their strengths. Total 10 subjects that the investigators have studied include both the static and dynamic problems related to such granular structures as artificial and/or natural slopes, ballast of railways, natural granular soil deposits with different grain size distributions.Stress was also put on developing new methodologies for visualizing and simulating the behaviors of grains because a granular material with relatively weak or no bonds among its grains never behaves like a continuous medium. LAT (Laser-Aided Tomography) is one of those new methods that allows all the grains shapes and motions as well within their assemblages to be clearly visualized by using glass grains, the liquid with the same refractive index as the glass and an intense laser-light sheet. A numerical simulation method, DEM (Discrete Element Method) was also used to examine grain-grain interaction and its effect on overall behavior of the granular mass.