Logging of Roofbolt Holes for Ground Characterization in Underground Construction
Characterization of the ground surrounding the tunnel is the key to improve the safety of tunnels and underground spaces during the construction. While the most common form of rock support at the present is bolting, obtaining information about the ground from the roof bolt drilling could be a logical step. In recent years, manufacturers such as J.H. Fletcher & Co have developed instrumented roof bolters which can detect bedding and discontinuities as well as rough estimation of the strength of the rock they drill through. This system enjoys a degree of success but requires further improvement and refinement, which is the goal of the current study. Borehole probing is an effective approach to interpret the ground conditions to allow for training of the smart roof bolter. This paper will discuss the recent achievements in the application of various probes such as optical televiewers for characterization of the ground in drill holes to be used for bolting.