An experimental method was developed to compare strain data for rock and rock bolts when exposed to shock waves released by blasting. During a 32-day period of experimentation, one rock sensor and four rock-bolt sensors were observed simultaneously. By their placement in the side wall of a structurally stable drift, secondary static stresses were excluded. Bolt gage responses, then, could be considered to originate only from a decay of anchorage stability during static conditions or as a reaction to the vibrations. Interpretation of test results indicated a distinct loss in bolt-strain during vibrations, accompanied by a smaller but steady loss of bolt-strain during static conditions. The strain losses were found related to the shock-source distance, the vibrational amplitudes in rock and bolts, and to the relative magnitude of vibrational energy in the two media --Abstract, page ii
