Development of grouting technologies for geological disposal of high level waste in Japan. 3. Numerical simulation for grout injection using equivalent continuum model

In this study, to simulate the grout injection process, the 3-D numerical model based on equivalent continuum approach was developed. The viscosity measurement for silica sol was performed to measure the time-dependent viscosity. The developed numerical model was applied to the planned in-situ grout injection tests at Grimsel test site (GTS), Switzerland. The rock type is fractured granite and the equivalent porous media was created from the Discrete Fracture Network (DFN) based on the fracture data obtained from the observation boreholes. The preliminary simulation was carried out to determine the suitable grout injection pressure and investigate the arrival distance of grout from injection boreholes. (author)