METHODS AND SYSTEMS FOR ULTRASONIC ROCK BOLT CONDITION MONITORING

A methods and systems for determining a change in condition of a rock bolt are disclosed. Some methods may comprise, at a first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a first time of flight for each of the shear and longitudinal waves, and at a second point in time after the first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a second time of flight for each of the shear and longitudinal waves. A temperature correction value is also determined. The first and second time of flights and the temperature correction value are used to calculate a temperature-corrected relative change between the first and second time of flights for each of the shear and longitudinal ultrasonic waves at the first and second points in time. Using the temperature-corrected relative changes of the first and second time of flights to determine the change in condition of the rock bolt.