Advanced excavation damage zone behaviour prediction for immediate and delayed construction response during deep tunneling and deep geological repository development

高水平核废料的处置是所有核电生产国面临的重大工程挑战。专家们的共识是，地下处置是唯一可行的长期选择。加拿大与许多国家一道，正在推进高水平(乏燃料)废物处理的研究和高级计划，目前正在为其自己的地下储存库选址。对于加拿大人来说，这样一个储存库的最终成本将是10‘S数十亿美元，长期的生存和安全依赖于围绕储存库基础设施产生的挖掘损害区的管理。安全评估主要涉及EDZ的最大范围和受损光环内流体流动性增加的梯度。 在EDZ内，是靠近开挖边界的更破碎的高度破坏区(HDZ)。EDZ/HDZ的阶段性、时变性和动态响应也是深埋隧道施工中的一个关键问题，具有较高的经济价值。在加拿大和世界各地，正在脆性岩石中越来越深的隧道被开发出来，用于民用基础设施或矿山通道。虽然通常被认为是采矿，但在最近的许多世界级隧道工程中，HDZ因施工而产生的脆性反应在设计阶段往往被忽视，严重影响了工人的安全，延误和增加了成本。 在核废料储存库中，竖井中可检测到的HDZ通常在回填之前的使用寿命结束时被移除，因此不在竖井安全评估中考虑。然而，在建设期间和之后，开发区的性质和随时间变化的反应将影响随后的开发区行为。在测序、安全和支持方面，这也将是一个工程挑战。不同的候选场地将有不同的预测脆性HDZ水平和动态破裂程度，这些必须在施工前识别，以便在设计中进行调整。 由这笔发现拨款资助的拟议研究建立在NSERC资助的先前进展的基础上(描述了损伤起始的一般性质)，现在专注于由应力路径、几何形状、岩性和地质结构控制的演化损伤，以及4D隧道施工序列中EDZ/HDZ的时间依赖性质和动态响应。最终结果将是脆性岩石深部施工的行为预测和风险管理方面的重大改进，提高工人的安全、支撑可靠性和监测有效性。这项工作将创造一个阶段性的变化 初步工程评估和设计的可靠性，显著 为价值数十亿美元的加拿大地下基础设施降低风险成本并提高项目可行性。 5名博士、7名硕士和3名USRA将在这个DG研究项目期间接受培训，并在国内和国际上获得了重要的曝光率。

Disposal of high-level nuclear waste is a critical engineering challenge for all countries that generate nuclear power. The expert consensus is that underground disposal is the only viable long-term option. Canada, along with numerous countries, is moving forward with research and advanced plans for high-level (spent fuel) waste disposal and is currently in the site selection process for its own underground repository. The ultimate cost to Canadians, of such a repository, will be 10's of $Billions and the long-term viability and safety relies on management of the Excavation Damage Zone (EDZ) induced around repository infrastructure. Safety assessment is primarily concerned with maximum extent of EDZ and the gradient of increased fluid mobility within this damaged halo. Within the EDZ is the more fractured highly damaged zone (HDZ) near the excavation boundary. The staged, time-dependent and dynamic response of the EDZ/HDZ is also a critical issue in deep tunnelling with comparably high economic value at stake. In Canada and around the world, tunnels are being developed at increasing depths in brittle rockmasses for civil infrastructure or mine access. While generally considered in mining, brittle response of the HDZ due to construction has often been overlooked at the design stage in many recent world-class tunnelling projects, with serious impacts on worker safety, delays and increased costs. In nuclear waste repositories, detectable HDZ in shafts is typically removed at the end of service life prior to backfilling and is therefore not considered in shaft safety assessment. The nature and time-dependent response of the HDZ during and after construction, will nevertheless impact the subsequent EDZ behaviour. It will also be an engineering challenge in terms of sequencing, safety and support. Different candidate sites will have different predicted levels of brittle HDZ, and degrees of dynamic rupture, which must be recognized prior to construction to enable adjustments in design. Proposed research funded by this Discovery Grant builds on previous NSERC-funded progress (characterizing the general nature of damage initiation), focusing now on evolving damage controlled by stress path, geometry, lithology and geostructure, and on the time-dependent nature and dynamic response of EDZ/HDZ during the 4D tunnel construction sequence. The end result will be major improvements in behavioural prediction and risk management for deep construction in brittle rock, improving worker safety, support reliability and monitoring effectiveness. This work will create a step change in reliability of preliminary engineering assessments and designs, significantly reducing risk costs and improving project viability for Canadian underground infrastructure worth $Billions. 5 PhD's, 7MSc's and 3 USRA's will trained during this DG research program and gain significant national and international exposure.