Research on backfilling and sealing of chambers and galleries in a repository in salt
The multibarrier concept for the final disposal of radioactive wastes comprises backfilling and sealing of the mine in order to guarantee a safe enclosure of the waste. Soil mechanical investigations were performed on salt grit and precompacted backfilling material of different grain-size distribution and clay admixtures. They showed a significant dependence upon permeability and compression velocity of the type and quantity of clay used. A favourable grain-size distribution of the salt resulted in an acceleration of its compactability. As well as the laboratory scale investigations, the long-term in situ behaviour of backfilled chambers and seals, and their corresponding geomechanical interaction with the surrounding rock, were determined at the Asse mine. The geotechnical in situ stress and deformation measurements in an approximately 27,000 m3 large chamber showed no supporting effect on the surrounding rock four years after backfilling. A compaction of up to 3% of the backfill was registered. In situ measurements as well as laboratory tests on drilling cores from a 60 years old backfill showed porosities of approximately 7% and a compaction effect on the backfill from the wall.
Bibliographic Reference: EUR 13955 DE (1992) 256 pp., FS, ECU 22.50
ISBN: ISBN 92-826-3690-9
Record Number: 199210325 / Last updated on: 1994-12-02
Original language: de
Available languages: de