Hydrogeological modelling with inflow volume and pressure response during groundwater recovery and discharge in shaft

Kumamoto, So*; Shimo, Michito*; Saegusa, Hiromitsu; Oyama, Takuya 

The Mizunami Underground Research Laboratory is being constructed by Japan Atomic Energy Agency in the Cretaceous Toki Granite in the Tono area, Central Japan. During construction, the information needed for testing and revising the hydrogeological model has been obtained. During shaft excavation, pumping of groundwater from the shaft has to be halted and the water level in shaft was recovered for the improvement of facility for treatment of discharged groundwater. This period was divided into three major phases, such as excavation, recovery and discharging phases, and hydraulic behavior in the phases was considered as a large-scale pumping test. In this study, model testing and calibration using the data of inflow volume and hydraulic behavior observed in these three phases have been carried out.