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

高放射性核废料的处置是所有核能发电国家面临的一项重大工程挑战。专家们一致认为，地下处置是唯一可行的长期选择。加拿大与许多国家沿着，正在推进高放射性（乏燃料）废物处置的研究和先进计划，目前正在为本国的地下处置库选址。对加拿大人来说，这样一个处置库的最终成本将是数十亿美元，长期的可行性和安全性取决于对处置库基础设施周围引起的挖掘破坏区（EDZ）的管理。安全性评估主要涉及EDZ的最大范围和该受损晕内液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损坏区（HDZ）。EDZ/HDZ的阶段性、时间依赖性和动态响应也是具有极高经济价值的深部隧道掘进中的关键问题。在加拿大和世界各地，正在开发越来越深的隧道在脆性岩体民用基础设施或矿山通道。虽然在采矿中通常被考虑，但在最近的许多世界级隧道施工项目中，HDZ因施工而产生的脆性反应在设计阶段往往被忽视，对工人安全造成严重影响，延误和成本增加。 在核废料储存库中，竖井中可检测的HDZ通常在使用寿命结束时在拆除之前被去除，因此在竖井安全评估中不被考虑。然而，施工期间和施工后HDZ的性质和时间依赖性反应将影响随后的EDZ行为。这也将是一个工程上的挑战，在排序，安全和支持。不同的候选场地将具有不同的预测脆性HDZ水平和动态破裂程度，必须在施工前进行识别，以便在设计中进行调整。 由该发现补助金资助的拟议研究建立在以前的NSERC资助的进展（表征损伤启动的一般性质）的基础上，现在重点关注由应力路径，几何形状，岩性和地质结构控制的不断变化的损伤，以及在4D隧道施工序列期间EDZ/HDZ的时间依赖性和动态响应。最终结果将是在脆性岩石中深层施工的行为预测和风险管理方面的重大改进，提高工人安全性，支持可靠性和监测有效性。这项工作将创造一个步骤的变化， 初步工程评估和设计的可靠性， 降低风险成本，提高价值数十亿美元的加拿大地下基础设施项目的可行性。 5名博士，7名硕士和3名USRA将在本DG研究计划期间接受培训，并获得重要的国家和国际曝光。

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.