The influence of particle characteristics on the behaviour of coarse grained soils
The influence of particle characteristics on the behaviour of coarse grained soils
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DOI：
10.1680/geot.2010.60.6.413
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发表时间：
2010-06-01
期刊：
影响因子：
5.8
通讯作者：
O'Sullivan, C.
中科院分区：
文献类型：
--
作者：
Cavarretta, I.;Coop, M.;O'Sullivan, C.
本文描述了一项实验研究，考察了组成颗粒的力学和几何特性对无粘性颗粒材料的整体材料响应的影响。玻璃泡沫塑料被用作模拟土壤，其相对简单的几何形状允许单独考察颗粒形状和颗粒间摩擦的影响。为了便于参数研究，开发了控制巴洛蒂尼表面粗糙度的技术。通过粉碎意大利香肠，颗粒形状也发生了变化。在微观尺度上，颗粒表征包括颗粒间摩擦力、接触刚度、颗粒表面粗糙度和颗粒形状的精确测量。在宏观尺度上，通过三轴试验和密实度计试验表征了整体材料响应对表面粗糙度和几何形状变化的敏感性，分别对光滑球形巴洛蒂尼、粗糙巴洛蒂尼和粉碎角度巴洛蒂尼进行了测试。压缩试验表明，颗粒-颗粒接触点的初始载荷变形响应比之前认为的要软得多。单颗粒-颗粒剪切试验后的颗粒光学干涉法证实，接触点处发生了塑性应变，这与塑性屈服有关。只有在较高的接触载荷下才能看到赫兹响应。颗粒间摩擦力与颗粒表面粗糙度之间存在明显的相关性。然而，宏观尺度的实验表明，虽然材料的响应可能与表面粗糙度和摩擦力略有关系，但颗粒形状的影响要显著得多。
This paper describes an experimental study examining the influence of the mechanical and geometrical properties of the constituent grains on the overall material response of cohesionless granular materials. Glass ballotini were used as an analogue soil; their relatively simple geometry allowed the influence of particle shape and inter-particle friction to be examined independently. Techniques were developed to control the surface roughness of the ballotini to facilitate a parametric study. The particle shape was also varied by crushing the ballotini. At the micro-scale, the particle characterisation included accurate measurements of inter-particle friction, contact stiffness, particle surface roughness and particle shape. At the macro-scale the sensitivity of overall material response to changes in surface roughness and geometry was characterised using triaxial tests and oedometer tests on smooth spherical ballotini, roughened ballotini and crushed angular ballotini. Compression tests indicated that the initial load deformation response at particle-particle contact points is significantly softer than previously believed. Optical interferometry of particles after single particle-particle shearing tests confirmed that plastic strains occurred at the contact point, which were related to plastic yield. A Hertzian response was only seen at higher contact loads. A clear relationship between the inter-particle friction and the particle surface roughness was found. However, the macro-scale experiments indicated that while the material response may be slightly dependent on the surface roughness and friction, the influence of particle shape is very much more significant.