Development and testing of the CMIN-BCM for monitoring borehole closure in underground environments

Steven Gaines, Ken Judge, Denis Labrie

In the proceedings of GeoSt. John's 2019: 72nd Canadian Geotechnical Conference

Session: Rock Mechanics

ABSTRACT: Monitoring borehole deformation during underground excavation activities is one method of evaluating rock mass performance during mining and tunneling. Continued monitoring and comparison to anticipated rock mass behaviour and/or existing stress models are important components of the engineering design and verification process. A comprehensive monitoring program provides real-time feedback of in situ rock behavior and delivers an added level of safety monitoring for underground works. Furthermore, accurate monitoring of borehole deformation can also be used to estimate changes to the induced stress field, and in turn, potential back analysis of the far field stress regime. CanmetMINING has developed a robust tool, referred to as the CanmetMINING Borehole Closure Meter (CMIN-BCM), for accurate and precise measurement of borehole deformation. The instrument, designed for use in 60 mm diameter boreholes, has a maximum range of 6.0 mm, resolution of 0.05 µm and accuracy of 5 µm over its full range. This paper presents a summary of instrument development and its specifications, as well as the results of bench scale and rock block laboratory testing. Future testing and development of the instrument will include a field testing program, including underground installation to monitor in situ conditions, as well as modifications to the external components of the instrument to increase its ability to withstand harsh field conditions. © 2019 Copyright reserved, Natural Resources Canada

RÉSUMÉ: lors du minage ou du creusement de tunnels. Le suivi en continu et la comparaison des observations au comportement anticipé pour le roc et de vérification en ingénierie. Un programme de suivi complet procure une évaluation en temps réel du comportement in situ des ouvrages et ajoute au degré de sécurité des travaux souterrains. Plus encore, un suivi rigoureux de la déformation des forages peut également être utilisé pour estimer les variations induites au champ de contrainte, et -analyse du régime de contrainte à grande échelle. CanmetMINES a développé un outil robuste appelé senseur de déformation des forages CanmetMINES (CMIN-BCM), pour mesurer de façon juste et orages de 60 mm de diamètre possède une course maximale de 6.0 mm, une résolution de 0.05 µm et une précision de 5 µm en pleine extension. Cet es lation du senseur dans un site souterrain pour suivre les conditions en place, de même que les modifications à © 2019 protégés, Ressources naturelles Canada.

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Cite this article:
Steven Gaines; Ken Judge; Denis Labrie (2019) Development and testing of the CMIN-BCM for monitoring borehole closure in underground environments in GEO2019. Ottawa, Ontario: Canadian Geotechnical Society.

@article{Geo2019Paper568,author = Steven Gaines; Ken Judge; Denis Labrie,title = Development and testing of the CMIN-BCM for monitoring borehole closure in underground environments ,year = 2019}