Hydrogeological investigations in Mizunami Underground Research Laboratory Project; Observation results of the "Deformation induced effect" due to the shaft excavation in Granite area

Toya, Naruhisa; Takeuchi, Ryuji  

The NNW fault, cross the MIU construction site, was identified from the previous study. In 2008, a borehole was drilled from gallery at GL-300m of the shaft. Several monitoring boreholes are located in the vicinity of the inferred NNW trending fault. The data from groundwater pressure monitoring at multiple depth intervals during the drilling activities show unique responses which seems to the deformation-induced effects. We report the possible application of using these hydraulic responses for characterizing the hydrogeological structures of the site.