Characterization of the excavation disturbance caused by boring of the experimental full scale deposition holes in the research tunnel at Olkiluoto

Three holes, the size of deposition holes, were bored in the research tunnel in Olkiluoto (in Finland) using a novel full-face boring technique. During the boring test procedures were carried out in order to determine the effect of changes in operating parameters on the performance of the boring machine and the quality of the hole. Evaluation of the quality of the hole included studies of the geometry of the holes, measurements of surface roughness using a laser profilometer, rock mechanical determinations and study of excavation disturbances in the zone adjacent to the surface of the holes using two novel methods, the He-gas method and the 14C-polymethylmethacrylate (14C-PMMA) method