In-situ measurement of permeability in rock mass using water including clay

Oketani, Kazuki*; Nara, Yoshitaka*; Matsui, Hiroya ; Fujii, Hirokazu*

For the geological disposal of radioactive wastes, it is important to understand the long-term migration of radionuclides. The network of fractures and pores in a rock mass, which have a role as the pathway of the fluid flow of materials, may change due to sealing of a material in the long term. We measured changes in hydraulic conductivity of crystalline rock mass using water mixed with clays sampled from a fault in the Mizunami Underground Research Laboratory, Japan Atomic Energy Agency. This result indicates that permeability of in-situ rock mass is possible to decrease by fracture filling with a clay material in a fault.