Study on engineering technologies in the Mizunami Underground Research Laboratory (FY 2014). Development of design and construction planning and countermeasure technologies (Contract research)

The study on engineering technology in the Mizunami Underground Research Laboratory (MIU) project consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies regarding restoration or reversal and mitigating of the excavation effect. The researches on engineering technology such as verification of the initial design were being conducted by using data obtained during Construction phase of the MIU project. The purpose of the study is to develop design and construction planning technologies, and countermeasure technology. And the analysis of data measured during earthquakes was performed to characterize the seismic movement at deep underground; also applied grouting methods were examined. As for 'Study on seismic movements at deep underground', all the data obtained from November 24th, 2008 to December 3rd, 2014 by measurement equipment, e.g. seismometers installed at ground level, and at 100m, 300m and 500m depth were analyzed to characterize the behavior of concrete lining and rock mass and to verify the earthquake-resistant design of the shafts in Phase I (Surface-based Investigation Phase). Overall evaluation of the relation between the geological condition and the seismic data obtained at each depth was performed. As for 'Study on grouting method at deep underground', post-grouting was conducted at the research gallery-south at 500m depth based on the test construction scheme established in FY2013 and its results were evaluated. Taking account of the task of the post-grouting method, further research plan was established. (author)