Contermeasure for the reduction of groundwater inflow due to the construction of the Mizunami Underground Research Laboratory

Takeuchi, Shinji; Hara, Masato; Mikake, Shinichiro ; Tsuruta, Tadahiko  ; Ikeda, Koki; Yamamoto, Masaru

The Mizunami Underground Research Laboratory (MIU) is currently being constructed. During its construction, water inflow into the shafts of the MIU has been increasing and affecting the project progress. In order to reduce the water inflow into the shafts, pilot borehole investigations and pre-excavation grouting have been planned. The pilot borehole investigations has been conducted from the shaft bottom at bothe of the Main (180mbGL) and Ventilation (191mbGL) shafts, respectively. The pre-excavation grouting has been undertaken in the Ventilation Shaft. The results of the investigations have showed applicability of several techniques applied.