Development of grouting technologies for HLW disposal in Japan, 4; Planning and results of in-situ grouting test

Tanaka, Tatsuya*; Uyama, Masao*; Ishida, Tomoko*; Nakanishi, Tatsuro; Onishi, Yuzo*

This paper describes the planning, material selection, execution and interpretation of the grout injection test carried out at the end of 2011 at the Grimsel Test Site (GTS) in Switzerland as part of grouting technology project of the Japan Atomic Energy Agency (JAEA). Based on the findings of the rockmass characterization part of the GTS grouting study (Nakanishi et al, 2012, Bruines et al., 2012), it was decided to perform the grout injection test in a 5 m interval with the highest expected hydraulic conductivity. During the grouting test the viscosity of the grout was continuously measured. Both the injected volume and pressure in the injection section were recorded. In the observation sections the pressure over time as well as the electric conductivity, which can be used to measure the arrival of the higher salinity silica grout, was recorded. As the grout reached the observation sections before the grout hardened the grout injection test was a success. The gathered data of the grouting test presents an important data set for further modeling efforts of the grouting process.