A Scale analysis of axisymmetric granular column collapses over a range of elevated gravitational accelerations

粒状流既可以在自然界中发现，如山体滑坡、泥石流和落石，也可以在食品和制药加工等一系列行业中发现。在本研究中，我们将重点放在环境设置上，其中颗粒流通常因水的存在和颗粒尺寸的巨大范围而变得复杂。在创建实验室原型时，这两个因素极大地改变了这些流动的比例。这些现象的最简单和研究充分的实验室规模表示之一是轴对称颗粒柱的崩溃。我们将使用这个起点来探索湿度、饱和度和粒径的影响，其数量级为10^6。为了在实验室尺度上物理地表示真实泥石流中流体的影响，我们必须人为地增加由于重力引起的加速度，以便在物理上小得多的流量下，依赖于g的速率保持平衡。计划开发一种轴对称颗粒柱坍塌实验，该实验将能够安装在位于大学公园L2大楼的岩土离心机上，以便在一系列升高的重力加速度下进行测试。本项目的主要成果如下：建立了轴对称颗粒柱倒塌试验综合数据库；重力加速度;饱和水平;粒度和分级；样本宽高比。分析来自这些实验的孔隙压力和图像数据，并与已发表的干柱崩塌数据和真实泥石流数据进行比较。确定决定流动结果的动态过程由哪个粒度范围控制。在简单的分析模型和可扩展的数值模型中实现这些发现。

Granular flows can be found both in nature, as landslides, debris flows and rockfalls, and across a range of industries, such as food and pharmaceutical processing. In this research, we focus on the environmental setting, where the granular flow is typically complicated by the presence of water and a huge range of particle sizes present. These two factors greatly alter the scaling of these flows when creating laboratory prototypes. One of the most simplistic and well researched laboratory scale representations of these phenomena is the collapse of an axisymmetric granular column. We will use this starting point to explore the effects of moisture, saturation and particle sizes ranging by orders of magnitude of 10^6. In order to physically represent the effects of fluid within a real debris flow at laboratory scale, we must artificially increase acceleration due to gravity, so that the g-dependent rates stay in balance despite physically much smaller flows. It is planned to develop an axisymmetric granular column collapse experiment that will be able to be mounted to the geotechnical centrifuge located in the L2 building on University Park in order to conduct tests over a range of elevated gravitational accelerations.The chief outcomes of the project are as follows: To develop a comprehensive database of axisymmetric granular column collapse experiments, varying parameters; gravitational acceleration; saturation level; particle size and grading; sample aspect ratio. To analyse pore pressure and image data from these experiments and compare with published dry column collapse data, and data from real debris flows. Establish which dynamic processes determining flow outcomes are governed by which particle size ranges. To implement these findings within simple analytical models and scalable numerical models.