Ultrasonic and Acoustic Emission Imaging of Brittle Fracturing Processes to Investigate the Progressive Failure of Rock

脆性断裂过程的超声波和声发射成像研究岩石的渐进破坏

• 批准号: RTI-2019-00065
• 负责人: Eberhardt, Erik
• 金额: $ 10.93万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=649905
• 关键词: Ultrasonic; Acoustic; Emission; Imaging; Brittle

***Canada is facing a new generation of engineering challenges involving deep underground excavations and resource extraction. Several mines are approaching 3000 m depth resulting in excavations experiencing significant stress-induced brittle failure and rock bursting hazards. This has significant implications for mine designs, including safe and effective support. Canada's nuclear waste management program is now searching for a site for a deep repository with the geological conditions necessary to satisfy safety requirements. Assessing the potential for stress-induced brittle fracturing is essential for this as the resulting excavation damage zone may increase the permeability of the rock acting as a geological barrier by 2 or 3 orders of magnitude. Hydraulic fracturing operations to enable production from Canada's unconventional gas reservoirs have been subject to public, industry, and regulator concerns regarding induced seismicity. Growing concerns are heightened due to knowledge gaps in our understanding of fault slip mechanisms and the factors controlling the likelihood and magnitude distribution of events. The experimental equipment being requested in this proposal will help us to accelerate our research programs addressing these challenges, by allowing us to image and therefore improve our understanding of brittle fracture processes and ability to measure and quantify their effects on rock strength, deformation and permeability change. ******The equipment requested will leverage an existing state-of-the-art rock testing facility capable of simulating the high stresses, pore pressures and temperatures experienced deep within the Earth, while measuring rock stress, strain, and permeability change. To this, the requested equipment will add unique capabilities to detect and image the initiation of brittle fracture damage and its evolution through progressive rock failure. Specifically, this includes simultaneously conducting time-lapse ultrasonic velocity imaging of brittle fracture damage anisotropy and failure localization, as well as detecting the source locations and source mechanisms of the brittle fractures generated using acoustic emissions (AE). We have a proven track record in experimental rock mechanics that is amplified by our ability to integrate experimental results with field-based observations, state-of-the-art numerical modelling, and new 4-D holographic visualization. This synergy leads to both improved experimental design and more robust interpretation of results. We have published extensively on these topics, and the requested equipment will allow us to continue to build upon our previous research successes. Separately, the equipment will also create numerous opportunities for interdisciplinary collaboration involving colleagues studying the role and evolution of brittle fracture processes related to CO2 sequestration, geothermal energy, and earthquake, landslide and volcano hazards.**

***加拿大面临着新一代的工程挑战，涉及地下深层挖掘和资源开采。一些矿井的深度接近 3000 米，导致挖掘过程中出现严重的应力引起的脆性破坏和岩爆危险。这对矿山设计具有重大影响，包括安全和有效的支持。加拿大核废料管理计划目前正在寻找一个具有满足安全要求所需地质条件的深层储存库地点。为此，评估应力引起的脆性断裂的可能性至关重要，因为由此产生的开挖损坏区域可能会将充当地质屏障的岩石的渗透性增加 2 或 3 个数量级。加拿大非常规气藏的水力压裂作业一直受到公众、行业和监管机构对诱发地震活动的关注。由于我们对断层滑移机制以及控制事件可能性和震级分布的因素的理解存在知识差距，人们越来越担心。本提案中要求的实验设备将帮助我们加快应对这些挑战的研究计划，使我们能够成像，从而提高我们对脆性断裂过程的理解以及测量和量化其对岩石强度、变形和渗透性变化影响的能力。 ******所需设备将利用现有的最先进的岩石测试设施，能够模拟地球深处经历的高应力、孔隙压力和温度，同时测量岩石应力、应变和渗透率变化。为此，所需的设备将增加独特的功能，以检测和成像脆性断裂损伤的起始及其通过渐进式岩石破坏的演变。具体来说，这包括同时进行脆性断裂损伤各向异性和失效定位的延时超声速度成像，以及使用声发射（AE）检测产生脆性断裂的源位置和源机制。我们在实验岩石力学方面拥有良好的记录，我们将实验结果与现场观察、最先进的数值建模和新的 4-D 全息可视化相结合的能力进一步增强了这一记录。这种协同作用既改进了实验设计，又提高了对结果的解释。我们已经就这些主题发表了大量文章，所需的设备将使我们能够继续在我们之前的研究成功的基础上继续发展。另外，该设备还将为跨学科合作创造大量机会，让同事研究与二氧化碳封存、地热能以及地震、滑坡和火山灾害相关的脆性断裂过程的作用和演变。**