Improved mechanical models & engineering management strategies for the excavation damage zone (EDZ) in sedimentary rocks around underground nuclear waste repositories

核废料的处理是一项关键的工程挑战。国际上的共识是，地下处置是唯一可行的选择。加拿大是一个主要的废物生产国，目前正处于沉积岩中包含的高级储存库的概念研究阶段。一个储存库的成本将超过200亿美元，成功取决于对储存库隧道、柱子和竖井周围的挖掘损伤区(EDZ)的准确预测和管理。EDZ是一套由扰动、损坏和破裂的岩石组成的同心带，可以为放射性核素提供路径。长期的研究目标是提高对机械损伤响应的理解，并在储存库规模上为沉积岩中损伤带的工程控制提供可靠的解决方案。未来5年DG研究的五个关键(短期)目标是： A.定义关键沉积岩(页岩和石灰岩)的损伤起始预测指标，包括受限、无限制和拉伸条件下的损伤之间的关系。这些与常规强度测试结果不同的阈值将校准现有的EDZ模拟数值分析工具。 B.评估和采用一些独特的数值代码和分析方法来分析各向异性(层状或层状)岩石中的EDZ，从而进一步开发出最有希望的技术，为EDZ模拟、预测和区域定义提供一个多工具策略。 C.区分预计的开发区扰动、损坏和破裂分区，量化开发区的影响，并为确定性和基于风险的开发区预测和管理制定工程指南，包括开挖方法选择和操作考虑因素，包括EDZ截止(密封)设计。 D.开发用于层状岩石中竖井/隧道施工期间损害评估的实时扫描技术，并将这些技术与实时开挖响应数据的收集和分析相结合。 这项研究将具有全国性的意义和影响。它将涉及国家和国际合作，为通过DG支助的10名研究生提供重大好处。

Disposal of nuclear waste is a critical engineering challenge. The international consensus is that underground disposal is the only viable option. Canada, a major waste producer, is currently at the concept research stage for a high-level repository contained in sedimentary rocks. The cost of a repository will exceed $20B and success relies on accurate prediction and management of the Excavation Damage Zone (EDZ) around repository tunnels, pillars and shafts. The EDZ is a suite of concentric zones of disturbed, damaged and fractured rock that can provide pathways for radio-nucleides. The long term research goal is to improve understanding of the mechanical damage response and robust solutions for engineering control of the damage zone in sedimentary rock, at an repository scale. The five key (short term) objectives for the next 5 years of DG research are: A. Define damage initiation predictors for key sedimentary rocks (shales & limestones) including the relationship between damage under confined, unconfined and tensile conditions. These thresholds, which differ from conventional strength test results, will calibrate existing numerical analysis tools for EDZ simulation. B. Evaluate and adapt a number of unique numerical codes and analysis methodologies for analysis of the EDZ in anisotropic (layered or bedded) rocks, leading to further development of the most promising techniques providing a multi-tool strategy for EDZ simulation, prediction and zone definition. C. Differentiate between the predicted disturbed, damaged and fractured sub-zones of the EDZ, quantify EDZ impact, and develop engineering guidelines for deterministic and risk-based EDZ prediction and management including excavation method selection and operational considerations including EDZ cutoff (seal) design. D. Develop real time scanning techniques for damage assessment during shaft/tunnel construction in layered rock and integrate these techniques with collection and analysis of real time excavation response data. This research will be of national significance and impact. It will involve national and international collaborations, providing significant benefit the 10 graduate students supported through the DG.