Hydrogeological characterization for estimation of hydraulic responses due to construction of the Mizunami Underground Research Laboratory

Saegusa, Hiromitsu; Shimo, Michito*; Kumamoto, So*; Onoe, Hironori ; Takeuchi, Ryuji  ; Takeuchi, Shinji; Oyama, Takuya 

One of the main goals of the Mizunami Underground Research Laboratory project is to establish comprehensive techniques for investigation, analysis, and assessment of the deep geological environment. Hydrogeological investigations using a stepwise manner have been carried out to obtain information on important properties. Hydrogeological modeling and groundwater flow simulations, which is for estimations of volume of inflow into underground tunnels and impact of construction of underground facilities on water table and hydraulic pressure, have been carried out by synthesizing these investigation results. From the study, the uncertainty of the hydrogeological model was evaluated and the main issues for further investigations were identified. Also, hydrogeological modeling and groundwater flow simulation using the data of hydraulic responses due to shaft sinking have been carried out in order to test/revise the models constructed in Phase I. These results are introduced in this paper.