Mizunami Underground Research Laboratory Project, Study on groundwater recovery experiment; Hydrological investigation and analysis during temporal decompression test

Ozaki, Yusuke  ; Kohashi, Akio; Keya, Hiromichi; Onoe, Hironori ; Takeuchi, Ryuji  

In Mizunami Underground Research Laboratory, groundwater recovery experiment test is performed at a part of research tunnel at 500m depth for research of recovery process of subsurface environment disturbed by construction of subsurface structure. During 2017, three times temporal decompression tests of hydraulic pressure in closure test drift keeping closed condition were conducted. We report the reproductivity of time variation of hydraulic pressure during the tests. We also report the estimation results of hydrogeological structure from the data during tests.