The Bentonite Rock Interaction Experiment (BRIE) at Äspö Hard Rock Laboratory (Äspö HRL) in Sweden aims at investigating the interaction between rock and bentonite in a deposition borehole. The main objectives are: Scientific understanding of the exchange of water across the bentonite - rock interface; Better predictions of the wetting of the bentonite buffer and; Better characterization methods of the canister boreholes. When selecting a site for BRIE, a location having low inflow, large depth (> 300 m), few fractures of varying (low) transmissivity but also homogeneous rock (matrix) was the goal. These are conditions that are also considered for canister boreholes for the future nuclear waste repository. In this paper hydromechanical characterization and behavior is of main interest.
The site selected for BRIE is located at 420 m depth in the TASO-tunnel of Äspö HRL. Investigations are ongoing and are performed in three different phases: 1) Selection of site (five primary boreholes); 2) Characterization of site (additional boreholes in floor and wall) and; 3) Characterization of two central boreholes. The boreholes are located along a 7 meter long stretch of the 5-meter diameter tunnel. When this is done, a final phase, 4) including installation and recovery of bentonite in order to investigate the interaction between rock and bentonite begins.
The project is carried out at the Division of GeoEngineering, research group Engineering Geology.