Study on grouting performance in the Mizunami Underground Research Laboratory; Modification and application of hydraulic test for grouting

Ando, Kenichi*; Takeuchi, Shinji; Matsui, Hiroya ; Tanaka, Tatsuya*; Hashimoto, Shuji*; Fujii, Haruhiko*

Evaluation of the effect of grouting on the geological environment is important for quality control of the design and management of the construction of underground facilities for high level radioactive waste disposal. Lugeon test has been commonly used to check the hydraulic characteristics around borehole whether or not to inject grout in Japan. The aim of this study is to develop a hydraulic test which can be applied to obtain hydraulic conductivities of low permeable rockmass (e.g. 10 to 10m/s) during grouting. The proposed hydraulic test with the test sequence of water injection and pressure recovery has been carried out in Mizunami URL excavated in crystalline rock. The developed type curve matching methodologies have been applied to evaluate hydraulic conductivity in-situ in a simple manner. Lessons learned for future application for grouting have been addressed.