Impact of shear induced pore pressures on the ground deformations around underground openings in weak shales

剪切引起的孔隙压力对软弱页岩地下开口周围地面变形的影响

• 批准号: RGPIN-2020-05324
• 负责人: Martin, Derek
• 金额: $ 4.52万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=749089
• 关键词: Impact; shear; induced; pore; pressures

Countries with argillaceous formations have been investigating these rocks to assess their potential for the disposal of nuclear waste. In Canada, the Nuclear Waste Management Organization (NWMO) has submitted a license application to construct a low and intermediate level nuclear waste repository at a depth of 680 m in clay rich Sedimentary rocks at the Bruce Site in Ontario, and argillaceous formations remains a possible target for used-nuclear fuel disposal. In Switzerland, Nagra has commenced an extensive site investigation program to characterise the Opalinus Clay, and in France, the Callovo-Oxfordian Formation has been selected by Andra for radioactive-waste-disposal characterisation. The nuclear waste industry demands that coupled geomechanical processes are sufficiently well understood to proceed with engineering design. In these argillaceous formations, the geomechanical processes are a function of complex rate and coupled phenomena. To validate our understanding of these coupled processes in situ, field measurements supported with extensive laboratory tests will be carried out to establish the relevant geomechanical processes applicable to repository design. In argillaceous rock, pore pressures must be measured to interpret the fundamental behaviour during the mechanical and thermal loading that will be encountered in a repository underground environment. This environment creates unique boundary conditions that have the potential to generate very large pore pressures on localized zones over large distances. Such pore pressures must be quantified and accounted for in the design of the repository. This research has three specific objectives: 1) Quantify and measure the anisotropic pore pressure response parallel and perpendicular to bedding as shearing progresses using fibre optic scale piezometers installed internally in conventional triaxial tests. 2) Simulate the repository stiffness and stress boundary conditions in a servo controlled direct shear device and quantify the pore pressure response on the shearing plane using internal fibre optic piezometers. 3) Utilize existing and new pore pressure data from a specifically designed test tunnel in the Opalinus Clay at Mont Terri, Switzerland, to re-evaluate the role of shear-induced pore pressures on the underground response. The long-term objective of this research is to establish and describe the appropriate in situ constitutive behaviour of clay shales needed for repository design. In parallel with this work will be the development of a methodology and framework for implementing a performance-based design.

具有泥质形成的国家一直在调查这些岩石，以评估其处置核废料的潜力。在加拿大，核废料管理组织（NWMO）已提交了许可申请，以在安大略省布鲁斯（Bruce）遗址的粘土富岩石岩石中建造一个低和中间水平的核废料存储库，而泥泞的地层仍然是二手核燃料分配的可能目标。在瑞士，Nagra开始了一项广泛的现场调查计划，以表征Opalinus Clay，在法国，Andra选择了Callovo-Oxfordian组成的放射性垃圾污垢 - 污点表征。核废料行业要求对地质力学过程耦合得充分了解工程设计。在这些泥质的地层中，地质力学过程是复杂速率和耦合现象的函数。为了验证我们对这些耦合过程的理解，将进行大量实验室测试支持的现场测量结果，以建立适用于存储库设计的相关地质力学过程。 在泥质岩石中，必须测量孔隙压力以解释在储存库地下环境中将遇到的机械和热负荷过程中的基本行为。这种环境创造了独特的边界条件，有可能在大距离内在局部区域上产生非常巨大的孔隙压力。在存储库的设计中必须量化此类孔隙压力。这项研究具有三个特定的目标：1）量化和测量各向异性孔隙压力响应平行，垂直于床上用品，随着剪切的前进，使用内部安装在常规三方测试中的光纤刻度压力仪进行剪切。 2）模拟伺服控制的直接剪切装置中的存储库刚度和应力边界条件，并使用内部光纤的光纤压力计量化剪切平面上的孔隙压力响应。 3）利用来自瑞士蒙特Terri的Opalinus粘土中专门设计的测试隧道的现有和新的孔隙压力数据，以重新评估剪切诱导的孔隙压力在地下响应中的作用。这项研究的长期目的是建立和描述存储库设计所需的粘土页岩的适当原位本构行为。与这项工作同时，将开发实施基于绩效设计的方法和框架。