From micro- to macro-scale characterization of geomaterials: the role of heterogeneities and scale in geomechanics

从微观到宏观尺度表征岩土材料：非均质性和尺度在地质力学中的作用

• 批准号: RGPIN-2019-07146
• 负责人: Grasselli, Giovanni
• 金额: $ 5.32万
• 依托单位: University of Toronto
• 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=739332
• 关键词: micro; macro; scale; characterization; geomaterials

Mechanical and geometrical properties of rock at grain (micro-) scale govern the behaviour of rock-masses at all scales. In recent years, my research group, among others, has developed and successfully used micro-mechanical hybrid finite/discrete element modeling techniques (FDEM) to simulate tunneling and other underground engineering activities. These results support the hypothesis that physically-based calibrated micro-mechanical models can inherently capture the heterogeneity and the scale effect observed in all geomaterials, and reproduce, as emergent behaviours, those underlying physical processes associated with complex failure mechanisms in rock (i.e., spalling, fracking, progressive slope instabilities). However, to date, no accepted procedure exists on how to relate micro-scale input parameters to specific lab measured values; thus, researchers have difficulties when it comes to soundly calibrating and verifying their models. Long-term goal of my research program: to understand the role that heterogeneities have, at all scales, on the behaviour of engineering and geological structures (i.e., tunnels, mines, reservoirs) subjected to varying multi-physics (Thermo-Hydro-Mechanical-Chemical) conditions, and to translate it into numerical solutions. Short-term objectives Obj.1 Understanding how spatial, volumetric, and scale distributions of heterogeneities influence localization and progression of deformational and failure processes. Obj.2 Development of a general methodology for the quantitative validation and calibration of micromechanical numerical codes. Obj.3 Development of a reproducible and reliable strategy for upscaling the use of micromechanical numerical codes to study rock behaviour at various spatial resolutions, from laboratory to tunnel/mine/reservoir scale. The validation process will evaluate the micro-scale physics implemented in the numerical codes and their ability to reproduce, as an emergent property of the model, macro-scale behaviours observed both in the laboratory and in the field. The novelty of this research program is the unique combination of advanced micromechanical laboratory investigations, empirical and machine learning analysis, and micromechanical FDEM modeling, to address a very old, but still unsolved problem in geomechanics: the scale effect. The anticipated outcome of this research will greatly contribute to reduce the scale-related uncertainties inherent to most geomechanical engineering projects (e.g., excavation of deep geological nuclear waste repositories, tunnels, mines, energy exploitation activities for shale oil and gas reservoirs), as well as increase confidence in rock engineering design. The research program offers a unique opportunity for HQP training in experimental and numerical geomechanics, a subject of great interest to the whole Canadian natural resource industry.

岩石在晶粒（微）刻度上的机械和几何特性决定了所有尺度上岩石质量的行为。 近年来，我的研究小组以及其他研究小组已经开发并成功地使用了微机械混合/离散元素建模技术（FDEM）来模拟隧道和其他地下工程活动。这些结果支持以下假设：基于物理的校准微力机械模型可以固有地捕获异质性和在所有地产中观察到的量表效应，并作为新兴行为繁殖，作为新兴行为，那些与岩石中复杂失败机制相关的基本物理过程（即，散布，是散布） ，压裂，渐进斜率不稳定性）。但是，迄今为止，如何将微尺度输入参数与特定的实验室测量值相关联的过程中尚无接受的程序；因此，研究人员在校准和验证模型方面遇到困难。我的研究计划的长期目标：了解异质性在各个范围内对工程和地质结构的行为（即隧道，矿山，储藏室）的作用（即受到不同多物理学的影响） - 化学）条件，并将其转化为数值解。 短期目标OBJ.1了解异质性的空间，体积和规模分布如何影响变形和故障过程的定位和进展。 OBJ.2开发一种通用方法，用于微机械数值代码的定量验证和校准。 OBJ.3开发可再现可靠的策略，以示意使用微机械数值代码在各种空间分辨率上研究岩石行为，从实验室到隧道/矿山/储藏量表。验证过程将评估数值代码中实现的微观物理及其重现的能力，作为模型的新兴特性，在实验室和现场都观察到了宏观尺度行为。该研究计划的新颖性是先进的微机械实验室研究，经验和机器学习分析以及微力机械FDEM建模的独特组合，以解决地质力学上的非常古老但仍未解决的问题：规模效应。这项研究的预期结果将极大地有助于减少大多数地质力学工程项目固有的与规模相关的不确定性（例如，深层地质核废料存储库的发掘，隧道，矿山，矿山，页岩油和天然气储量的能源开发活动）以及随着对岩石工程设计的信心增加。该研究计划为实验和数字地质力学方面的HQP培训提供了独特的机会，这是整个加拿大自然资源行业引起的极大兴趣的主题。