Countermeasures planned for reducing water inflow into deep shaft; Contact research at the Mizunami Underground Research Laboratory

Kuji, Masayoshi*; Asai, Hideaki; Mikake, Shinichiro ; Hara, Masato

The Mizunami Underground Research Laboratory is currently being constructed by Japan Atomic Energy Agency. During its excavation, large amount of water inflow into the shafts has been increasing and affecting the project progress. As countermeasures for reducing water inflow, grouting methods are being considered, one is post-excavation grouting for the area already excavated, and another is pre-excavation grouting for the area excavate in future. Therefore, the field experiment for post-excavation grouting was carried out, and the result show that the applied methods in this field experiment is effective to prevent the draining. And pre-excavation grouting has been undertaken and the applicability of several techniques has been evaluated. This report describes the summary of the Mizunami Underground Research Laboratory and field experiments of post- and pre-excavation grouting method.