Development of grouting technologies for geological disposal of high level waste in Japan (7). Hydrological and chemical change of the groundwater in a pre-grouted crystalline rock after earthquakes

The Japan Atomic Energy Agency has conducted 'The project for Grouting Technology Development' under a contract study with the Ministry of Economy, Trade and Industry (METI). As a part of the study, the groundwater chemistry has been monitored for four years after pre-grouting the crystalline rock in the Mizunami underground research laboratory (URL). Measured groundwater pressures were temporarily changed by earthquakes of seismic intensity ≥ 3 and recovered within about one year. Changes to the chemical composition of the groundwater by the earthquakes were not detected and the injected grout material was not significantly damaged. (author)