Determination of the porosity, permeability and diffusivity of rock in the excavation-disturbed zone around full-scale deposition holes using the ~14C-PMMA and He-gas methods

摘要

Three experimental holes the size of deposition holes in a KBS-3 type repository(depth 7.5 m and diameter 1.5 m)were bored in hard granitic rock in the Research Tunnel at Olkiuoto to study, among other things, the properties of the rock in the excavation-disturbed zone. In the analysis described in this report, the porosities, effective diffusivities and permeabilities of disturbed and intact rock were determined by using two novel methods: the ~14C-polymethylmethacrylate method and the He-gas method. In addition, the structure of the rock in the excavation-disturbed zone was assessed using both scanning electron and optical microscopy.