Fissures and boreholes plugging in fractured geologic deposits (granites)

This report gives the results of bench-scale experiments and field tests, destined to describe the bentonite behavior in fractured scale models and in boreholes, and to allow to study the rock weathering phenomenons under specific conditions. Dry and compact bentonite, used for exploratory drilling plugging, in crystalline rock deposits and in contact with groundwater, show hydration, swelling and mobility properties with penetration in conducting fractures. The purpose of this work is to define the procedure of clay weathering after the swelling phase, under groundwater circulation effect, to estimate plugs longevity. This study is prepared for the European Atomic Energy Community cost-sharing research program on radioactive waste management and disposal. 63 refs., 100 figs., 30 tabs., 17 plates