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

将核废料存放在深层地质储存库(DGR)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，将存储库与周围的地质环境隔离开来。然而，挑战在于，就像任何地下开挖一样，在被称为开挖损伤区(EDZ)的平坦开挖过程中，周围的围岩将受到破坏。损伤萌生和断裂扩展是随着裂隙强度的减小而发生的，直接影响到围岩的渗透性。目前，对开发区内的即时和临时变化的评估是通过数值模拟和在可以进行现场测试的全面地下实验室进行的。这些地下实验室依赖于在开挖试验场后对寄主岩石进行物理采样以及非破坏性地球物理方法。这两种方法在总体疗效上都有一定的局限性。所有这些方法都不能在整个测试设施的生命周期中实时地完全表征开发区的时间地质力学特性。

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.