Fracture research at an underground laboratory

Microseismic (MS) monitoring is used around the world to monitor the performance of mines, underground storage facilities and provide information on hydrocarbon extraction. The data presented here are from the Canadian Underground Research Laboratory (URL) operated by Atomic Energy Canada Ltd. (AECL). This facility has been constructed to carry out fundamental research in rock and fracture mechanics as part of investigations into the feasibility of underground storage of nuclear waste.

The URL 440m level is currently monitored using a 48-channel microseismic acquisition system to record MS events (failure over 10s of centimetres) around a network of tunnels. To enable source mechanism work to be performed an array of sixteen triaxial accelerometers are installed around the 100x100x100m volume. The diagram below shows (on the left) a picture taken in the 'Mine-by' tunnel. The notching in the roof and floor that developed after excavation is evident. The diagram on the right hand side shows the location of microseismic events which are associated with the notching process.

An ultrasonic monitoring system has also been installed around a section of the Tunnel Sealing Experiment (a 10x10x10m volume) which was funded jointly by AECL, JNC (Japan), ANDRA(France), and WIPP (USA) to investigate smaller microfracturing on the AE scale (millimetres in dimension) and AE interactions to form MS events. These monitoring systems are being used to understand the processes associated with fracture mechanics and the relationship between stress changes and induced seismicity.



We thank AECL for their kind permission to use this data on our website.


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