Carbonated water injection into mudstone rock mass in Horonobe, Hokkaido

Kamata, Kento*; Nara, Yoshitaka*; Matsui, Hiroya ; Ozaki, Yusuke  ; Fujii, Hirokazu*; Zhao, Y.*

In this study, we perform a carbonated water injection experiment into the fractured rock to investigate the reduction of permeability due to the sealing of fractures by the precipitation of carbonated minerals at the 350m stage in Horonobe URL. We drilled a 80cm borehole from the drift wall and injected the carbonated water into the fractures there in the excavated damaged zone. The hydraulic test that we performed regularly during the injection experiment indicates the reduction of hydraulic conductivity slightly. To understand the mechanism of the reduction of permeability, we plan to analyze the core sample collected by overcoring.