Development of grouting technologies for HLW disposal in Japan, 2; In-situ grouting test program and site investigation results at the Grimsel Test Site in Switzerland

Nakanishi, Tatsuro; Tsuda, Hidenori; Abumi, Kensho*; Uyama, Masao*; Onishi, Yuzo*

JAEA has been developing grouting materials and technologies with the consideration of long term chemical interaction between the grout material and the rock mass as a natural barrier. This paper describes the in-situ grout injection test program carried out in the fractured granite of the Grimsel Test Site (GTS) in Switzerland, which has been set up to increase knowledge and understanding of the design of grouting in order to reduce the grout penetration area into the rock mass and of the results of the site investigation. The grout injection test project at the GTS has been carried out in several stages. The site investigation results of all six boreholes were then used to determine the best location for the final grout injection test. The staged approach proved to be a good way not only to determine the best location for the grout injection test, but also to focus on the best approach in the next stages by identifying and mitigating possible problems before they occurred.