ABSTRACT
Two decades ago, the author along with his research group and industrial sponsor began to develop a novel Rayleigh-based distributed optical strain sensing technology capable of monitoring strain along a temporary support scheme at sub-centimeter spatial resolution. This line of research has been extended to monitor Fully Grouted Rock Bolts (FGRB) and rock mass deformation with an increased resolution of sub-millimeter spacing (0.65 mm). This non-trivial optical technique has been tested in the laboratory and has since been implemented at multiple active tunnelling and mining sites around the world. Within this context, this paper summarizes selected lessons learned over the past two decades regarding the use of fiber optics for monitoring the ground conditions and support elements utilized in underground excavations while also highlighting the evolution of the research, development, implementation and impact of this sensing technique with a view to optimizing and improving tunnel support design.
