Comparison of grouting with silica sol in the sp Hard Rock Laboratory in Sweden and Mizunami Underground Research Laboratory in Japan

Tsuji, Masakuni*; Funehag, J.*; Kobayashi, Shinji*; Sato, Toshinori  ; Mikake, Shinichiro 

Silica sol is a material that seems to fulfill the non-hazardous requirement and capable of penetrating into narrow fractures. The rock grouting strategy with silica sol has been studied and applied for some recent projects in Sweden. The design methodology is based on the determination of the fracture transmissivity distribution and the theoretical penetration length. In 2008, grouting with silica sol was applied in the construction of a short tunnel at 450 m depth in the sp Hard Rock Laboratory, the TASS-tunnel. In 2010, a grouting experiment with silica sol was performed in a gallery at 300 m depth in the Mizunami Underground Research Laboratory (MIU experiment). It can be suggested that Swedish methodology can be applied to design and evaluate the grouting works in Japanese rock with higher intensity of fractures in general. Furthermore, an additional pumping time or the use of Japanese silica sol might improve the grouting quality in Sweden.