Determination of Extent of Excavated Damage Zone Around Mined Tunnels using Pre and Post Construction Pore-Water Pressure Response

* * * 正常 * 0 * 假 * * EN-US* JA* X-NONE* * * * * * * * * * * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** /* 样式定义 */*table.MsoNormalTable* {mso-style-name：“Table Normal”;* mso-tstyle-rowband-size：0;* mso-tstyle-colband-size：0;* mso-style-noshow：yes;* mso-style-priority：99;* mso-style-parent：“";* mso-padding-alt：0cm 5.4pt 0cm 5.4pt;* mso-para-margin-bottom：0cm;* mso-para-margin-bottom：.0001pt;* mso-pagination：widow-orphan;* font-size：12.0pt;* font-family：Cambria;* mso-assign-font-family：Cambria;* mso-assign-theme-font：minor-latin;* mso-hansi-font-family：坎布里亚;* mso-hansi-theme-font：minor-latin;* mso-ansi-language：EN-US;}* 将核废料封存在深层地质处置库（DGR）中是全球长期处置乏核燃料的首选方法。DGR的好处是存在工程和地质屏障，将处置库与周围地质环境隔离开来。挑战;然而，与任何地下工程开挖一样，在平硐开挖过程中围岩也会受到破坏，即开挖损伤区。损伤起裂和断裂扩展是随着裂纹强度的减小而发生的，它直接影响到围岩的原位渗透性。 目前，通过数值模拟和可进行现场测试的全尺寸地下实验室对EDZ内的即时和时间变化进行评估。这些地下实验室依赖于测试平硐开挖后对围岩的物理取样以及非破坏性地球物理方法。这两种方法在其总体功效方面都有一定的局限性。 这些方法中没有一种能够在测试设施的整个寿命期间实时地完全表征EDZ的时间地质力学特性。* 最近的研究表明，高分辨率压力计对气压载荷的响应（通常称为地质压力计）可用于表征深层页岩弱透水层的刚度和水力传导性（Smith等人1，2）。拟议的研究计划的总体目标是推进当前的方法来评估在中间地质材料中建造的隧道周围EDZ的发展和范围。短期目标包括进行全面的基础和应用研究，以评估地质渗透计的潜在用途：（1）确定现场刚度随时间和距离隧道壁的变化（2）确定EDZ内围岩导水率随时间的变化;以及（3）扩展了隧道施工过程中应力旋转的现有知识，以及伴随的超孔隙水压力（孔隙弹性）响应对EDZ整体尺寸和形状的影响。我的长期目标是帮助加拿大人走在隧道建设技术和核废料储存的最前沿。从这项研究计划中获得的知识将是我们评估和界定EDZ在目前计划用于DGR建设的各种宿主岩石中的潜在影响的能力的关键组成部分。结果的潜在用户包括核管理组织、环境保护机构、工业和政府决策者。模型的改进也可适用于加拿大和世界各地的DGR，以帮助为相关决策提供信息。

* * * *** * Normal* 0* * * * * false* false* false* * EN-US* JA* X-NONE* * * * * * * * * * * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * **** /* Style Definitions */*table.MsoNormalTable* {mso-style-name:"Table Normal";* mso-tstyle-rowband-size:0;* mso-tstyle-colband-size:0;* mso-style-noshow:yes;* mso-style-priority:99;* mso-style-parent:"";* mso-padding-alt:0cm 5.4pt 0cm 5.4pt;* mso-para-margin:0cm;* mso-para-margin-bottom:.0001pt;* mso-pagination:widow-orphan;* font-size:12.0pt;* font-family:Cambria;* mso-ascii-font-family:Cambria;* mso-ascii-theme-font:minor-latin;* mso-hansi-font-family:Cambria;* mso-hansi-theme-font:minor-latin;* mso-ansi-language:EN-US;}****The containment of nuclear waste in deep geological repositories (DGR) is the preferred method for long-term disposal of spent nuclear fuel globally. The benefit of a DGR is the presence of both engineered and geological barriers that isolate the repository from the surrounding geological environment. The challenge; however, is that like any underground excavation, the surrounding host rock will be damaged during adit excavation known as the excavated damage zone (EDZ). Damage initiation and fracture propagation occurs with the crack intensity decreasing with distance from the tunnel wall, which has a direct influence on the in situ permeability of the host rock. Currently, assessment of the immediate and temporal changes within the EDZ is carried out through numerical simulation and in full-scale underground laboratories where field tests can be conducted. These underground laboratories rely on physical sampling of the host rock following excavation of test adits as well as non-destructive geophysical methods. Both of these methods have some limitations in their overall efficacy. None of these methods can fully characterize the temporal geomechanical properties of the EDZ on a real-time basis throughout the life of the test facility. ***Recent studies have demonstrated that the response of high resolution piezometers to barometric loading, often referred to as geolysimeters, can be used to characterize both the stiffness and hydraulic conductivity of deep shale aquitards (Smith et al.1,2). The overall goal of the proposed research program is to advance current methods to evaluate the development and extent of the EDZ around tunnels constructed in intermediate geomaterials. The short-term objectives involve conducting comprehensive fundamental and applied research to evaluate the potential use of geolysimeters to: (1) determine the change of the in situ stiffness with time and with distance from the tunnel wall (2) determine the change in the hydraulic conductivity of the host rock within the EDZ with time; and (3) extend the current knowledge of stress rotations during tunnel construction and the impact of the accompanying excess pore-water pressure (poroelastic) response on the overall size and shape of the EDZ. My long-term objective is to help place Canadians at the forefront of tunnel construction technologies and nuclear waste storage.***Knowledge gained from this research program will be a critical component in our ability to assess and bound the potential implications of the EDZ in various host rocks currently planned for DGR construction. The potential users of the results include nuclear management organizations, environmental protection agencies, industry, and governmental decision makers. The model improvements may also be adapted for use in DGRs, in Canada and worldwide, to help inform relevant decisi