Current status and next five-year plan of R and D activities of Mizunami Underground Research Laboratory

Mikake, Shinichiro ; Iwatsuki, Teruki  ; Matsui, Hiroya ; Sasao, Eiji   

The MIU (Mizunami underground research laboratory project) has proceeded in three overlapping phases, "Phase I: Surface-based investigation", "Phase II: Construction" and "Phase III: Operation". The construction of research galleries in the MIU has been completed to the GL-500 m depth. The research activities in Phase III have been conducted in the underground since 2010. Current R and D activities include a gallery closure test on the -500m level to study recovery processes in the geological environment around a gallery after it has been backfilled and for the development of long-term monitoring technology, a post-excavation grouting experiment to demonstrate the feasibility of impermeable grout technology, and a mass transport experiment. This report introduces the next five years R&D plan and its current status.