Case study about fault distribution and influence to geological environment in Mizunami Underground Laboratory

Nohara, Tsuyoshi   ; Sakai, Toshihiro; Ishibashi, Masayuki; Matsumoto, Jun*

Data analysis about the distribution of the high-angle fault (Main-shaft fault) and the water permeability in the granite was performed in MIU. We recognized wide range of strike of a fault and that the spray fault and the fault crowd are observed in a shallow depth in the tunnel scale. I could think fault and altered-zone distributed successively, and formed a low permeable zone.