Development of a guided wave inspection technique for rock bolts

Rock bolts are used to reinforce coal mine roadways, and a suitable non-destructive test for their integrity is required. Research has been carried out into the use of guided ultrasonic waves to inspect rock bolts, using a pulse-echo test configuration. Suitable high and low frequency modes have been identified through the use of modelling software, and successful site trials have been undertaken in a limestone mine as well as on laboratory specimens. The research has shown that the proposed approach is feasible, and also that there are opportunities for the inspection of other embedded structures.