Identifying mechanisms of environmentally driven long-term crack growth in brittle rocks

识别环境驱动的脆性岩石长期裂纹扩展的机制

• 批准号: RGPIN-2018-05918
• 负责人: Perras, Matthew
• 金额: $ 2.26万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=683901
• 关键词: Identifying; mechanisms; environmentally; driven; long

Cracks forming in rock near the surface of an excavation or at the Earth's surface can result in critical damage to existing infrastructure, disruption of operations, and loss of life when unexpected failures occur. Even if critical damage is not caused, the cracks formed can result in problematic flow pathways for containment facilities. Typically, empirical and numerical designs focus on the extent of damage and mitigation measures, with little attention to long-term processes. In addition, the influence of environmental drivers on crack growth remains a frontier of research. To improve engineering practice to the point that environmentally driven long-term crack growth mechanisms, the associated hazards and proper mitigation strategies are included in design is the long-term goal of this program. The program includes developing field monitoring methodologies, designing laboratory testing scenarios that reflect the field conditions, and using these findings to develop and validate hazard assessment and predictive numerical tools. ***In the short-term, the research program will aim to determine the most suitable numerical software to model environmental influence of long-term crack growth, to understand the influence of thermal cycles on the magnitude of crack opening and growth at different scales, to determine if stress corrosion in stressed brittle rock is a dominate crack growth mechanism over other identified mechanisms, and to evaluate the transferability of different data sources from one field location to another. ***The methods to be used to address the objectives mentioned above will include a variety of field, laboratory, and numerical modelling approaches. For the field sites, geological mapping, strength estimation and sample collection, advanced photogrammetric and spatial analysis of the results will augment the monitoring data to address the transferability of this information to new locations. In the laboratory, standard strength and advanced long-term tests under variable climates will be used to characterize the rock and crack behaviour and develop inputs for numerical models. Models to back analyze both the field and laboratory behavior will be computed and compared with different approaches from common engineering to advanced multi-physics and fracture mechanics software. These findings will lead to new testing procedures, novel methods of monitoring and utilizing monitoring data, and most importantly will lead to the development of much needed numerical tools to capture long-term crack growth mechanisms. ***With the applicant's past experience in these areas, along with a team of HQP, the program will make major advances in the areas of rock and fracture mechanics, and near surface process research. Major impacts on the way the Civil Engineering community thinks about and deals with environmental influences on long-term crack growth are expected.

挖掘地表附近或地球表面的岩石中形成的裂缝可能会导致现有基础设施严重损坏、运营中断，并在发生意外故障时造成人员伤亡。即使没有造成严重损坏，形成的裂缝也会导致安全壳设施的流动路径出现问题。通常，经验和数值设计侧重于损害的程度和缓解措施，而很少关注长期过程。此外，环境驱动因素对裂纹扩展的影响仍然是研究的前沿。该计划的长期目标是改进工程实践，将环境驱动的长期裂纹扩展机制、相关危害和适当的缓解策略纳入设计中。该计划包括开发现场监测方法、设计反映现场条件的实验室测试场景，以及利用这些发现来开发和验证危害评估和预测数值工具。 ***短期内，该研究计划的目标是确定最合适的数值软件来模拟长期裂纹扩展的环境影响，以了解热循环对不同尺度裂纹张开和扩展的影响，以确定受应力脆性岩石中的应力腐蚀是否是比其他已识别机制占主导地位的裂纹扩展机制，并评估不同数据源从一个现场位置到另一个现场位置的可转移性。 ***用于实现上述目标的方法将包括各种现场、实验室和数值建模方法。对于现场，地质测绘、强度估计和样本收集、先进的摄影测量和结果的空间分析将增强监测数据，以解决这些信息向新地点的转移问题。在实验室中，将使用可变气候下的标准强度和先进的长期测试来表征岩石和裂缝行为并开发数值模型的输入。将计算用于支持分析现场和实验室行为的模型，并与从普通工程到先进的多物理场和断裂力学软件的不同方法进行比较。这些发现将带来新的测试程序、监测和利用监测数据的新方法，最重要的是，将导致开发急需的数值工具来捕获长期裂纹扩展机制。 ***凭借申请人过去在这些领域的经验以及HQP团队的帮助，该项目将在岩石和断裂力学以及近地表过程研究领域取得重大进展。预计会对土木工程界思考和处理长期裂缝增长的环境影响的方式产生重大影响。