Behaviour of full grouted rock bolts subjected to repeated dynamic loading

In order to investigate the effect of repeated dynamic loads on mechanical properties of the rock bolts. Based on the Split Hopkinson Pressure Bar (SHPB) system, a new device was introduced to study the effect of the dynamic load on rock bolts, including its layout and principle. The slippage of the rock bolt and the propagation of semi-sine stress waves in the bolt were investigated. The damage mechanisms of rock bolts under the dynamic loading were discussed briefly. The test results indicate that the failure of rock bolt is closely associated with the dynamic load. The anchorage zone has been damaged owing to the effect of the first dynamic load, and this damaged zone is further extended from the second dynamic load and rock squeezing, etc.), and it will be unable to resist the deformation of the surrounding rock.