Multi-scale testing and modeling particle size effects on primary and secondary compressibility of crushable granular materials

多尺度测试和建模粒度对可破碎颗粒材料初级和次级压缩性的影响

• 批准号: RGPIN-2019-06118
• 负责人: OvalleOrtega, Carlos
• 金额: $ 1.89万
• 依托单位: École Polytechnique de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=738721
• 关键词: Multi; scale; testing; modeling; particle

Granular fills are widely used in civil engineering and the understanding of their mechanical properties is essential. A key issue in the stress-strain behavior is particle breakage. Briefly, when intergranular contact forces exceed particle strength, a fraction of the particles could crush, changing the grain size distribution towards a finer and more polydisperse material. Consequently, the compressibility increases for a given stress state. Furthermore, particle breakage is the source of size effects and creep strains in granular materials, which could be significant in engineering and geoscientific problems, involving high rockfill dams, pile penetration, granular fills in discontinuities of rock masses, rock fragmentation by weathering, subsidence of fractured rock deposits, among others. Several phenomenological constitutive models for crushable granular materials have been developed according to macro-mechanical observations, based on relationships between the amount of breakage and the compressibility through fitted parameters. However, the source of grain crushing comes from the fracture mechanics of individual grains. In other words, it depends on geometrical and mineralogical characteristics of individual grains, on their loading conditions through particle contacts and on environmental conditions. Therefore, in order to develop physical-based methods, multi-scale approaches seem appropriate, but only a few attempts have been made on this subject and experimental data is quite scarce. In this research program, a comprehensive experimental work and theoretical developments are proposed in order to study the multi-scale mechanisms involved in particle size effects on primary and secondary compressibility of crushable granular materials. The program will allow a broad analysis through micro, meso and macro-scales. Practical applications of this research will be of great interest for geotechnical engineering, as well as other disciplines dealing with the mechanics of granular materials, such as powder technology in the ceramic, pharmaceutical, food and mining industries, for instance.

颗粒填充物广泛用于土木工程，对其机械性能的理解至关重要。应力应变行为的一个关键问题是粒子破裂。简而言之，当晶间接触力超过粒子强度时，一小部分颗粒可能会挤压，将晶粒尺寸分布更改为更细，更多的多分散材料。因此，给定应力状态的可压缩性增加。此外，粒子破裂是颗粒材料中尺寸效应和蠕变菌株的来源，在工程和地球科学问题上可能很重要，涉及高岩石大坝，桩渗透，颗粒状填充岩石质量的不连续性，岩石碎片，岩石碎片，面对面，沉降，沉降，沉降，沉重的沉降，岩石碎片岩石沉积物等破裂。根据宏观机械观测，已经根据拟合参数的破裂量和可压缩性之间的关系，根据宏观机械观测来开发了几种现象学构成模型。但是，谷物粉碎的来源来自单个谷物的断裂力学。换句话说，这取决于单个晶粒的几何和矿物学特征，通过粒子接触和环境条件，其负载条件。因此，为了开发基于物理的方法，多尺度方法似乎合适，但是对此主题进行了一些尝试，实验数据很少。在该研究计划中，提出了一项全面的实验工作和理论发展，以研究涉及粒径对可碎颗粒物材料的原发性和二级可压缩性的涉及的多尺度机制。该程序将允许通过微型，中索和宏观尺度进行广泛的分析。这项研究的实际应用将引起岩土工程的极大兴趣，以及其他有关颗粒状材料机制的学科，例如陶瓷，药品，食品和矿业行业中的粉末技术。