The Groundwater pressure response due to shaft excavation and its possible application for characterizing hydrogeological structure

Toya, Naruhisa; Takeuchi, Ryuji  ; Tokunaga, Tomochika*; Aichi, Masaatsu*

Excavation of the Mizunami Underground Research Laboratory began in 2003. In 2006-2007, several boreholes were drilled from the shafts and the gallery at GL-200m. Several monitoring boreholes are located in the vicinity of the NNW striking fault. The data from groundwater pressure monitoring obtained at multiple depth intervals during the drilling activities show unique responses, which resemble deformation-induced effects. In this study, we report the possible application of using these hydraulic responses for characterizing the hydrogeological structures of the site.