Publication Date:
2014-04-09
Description:
In the framework of the SB experiment (‘Self-sealing barriers of sand/clay mixtures’), a series of small in situ tests in several vertical boreholes were installed in October 2005 at the underground rock laboratory at Mont Terri. The boreholes were backfilled with sand/clay mixtures at different ratios as well as pure MX-80 bentonite. At the GRS laboratory the experimental setup was installed in advance and has run under nearly the same boundary conditions since March 2005. Sand/clay mixtures exhibit a high permeability to gas in the dry state and a low gas entry pressure and moderate permeability to gas in the saturated state, while the permeability to water is comparable to that of the undisturbed host rock. Therefore, gaseous corrosion products will be preferentially conducted through the seal, mitigating the risk of opening new pathways (fractures) in the host rock. The main objective of the SB experiment presented here is to test and demonstrate that the advantageous sealing properties of clay/sand mixtures determined in the laboratory can technically be achieved and maintained under repository-relevant in situ conditions.
Print ISSN:
0305-8719
Electronic ISSN:
2041-4927
Topics:
Geosciences
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