社団法人 物理探査学会
第138回(平成30年度春季)学術講演会


水平坑道掘削に伴う掘削影響領域の調査−幌延深地層研究施設における検討−

講演要旨(和文)
本研究では、掘削影響領域における水理・力学・物理特性等を調査し、掘削影響領域の範囲や掘削影響領域において生じた物理変化の要因、およびその経時変化を評価することを目的に、幌延深地層研究施設の深度140、250mにおける水平坑道を利用して、弾性波・比抵抗トモグラフィなどの各種試験を行った。

講演要旨(英文)
In an excavation of shafts and galleries in the deep underground for disposing high level radioactive waste, an excavation disturbed zone (EdZ) or excavation damaged zone (EDZ) is developed around the shafts and galleries owing to the stress redistribution. It is important to understand the behavior of the EdZ or EDZ because these zone could have an effect on the transfer behavior of radioactive nuclide. Therefore, the authors performed the in situ experiment to investigate the behavior of EdZ or EDZ in the 140m and 250m gallery in the Horonobe Underground Research Laboratory. From the result of the experiments, the authors compared the characteristics of EdZ or EDZ between those in 140m and 250m gallery. The extent of the fractures induced by the gallery excavation, i.e., EDZ was about 0.45m in the 140m gallery and about 1m in the 250m gallery. The extent of the unsaturated zones related with EdZ was about 1m in the 140m gallery, however, unsaturated zone was not appeared in the 250m gallery.