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

点击翻译按钮获取中文摘要

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.