Abstract: By model test, the stress distribution of anchored rockbolts close to working face is studied when subjected to blast loading. Based on similar condition, simplification and hypothesis, engineering cutting blasting was simulated in mass charge. Axial strain waves measured from strain gauges mounted on rockbolts were recorded considering both of end-anchored and full grouted rockbolts. Test results show that rockbolt vibration approximately ceases after duration of 6 ms and then bolt deformation keeps stable in 9 ms. For end-anchored bolts, peak stress on middle locations of bolts in anchor section is slightly greater than the value of tail location in smooth section when bolts are subjected to blast loading; but the latter presents a greater residual stress. For full grouted bolts, peak stress and residual stress measured on tail section exceed the values on central section. Utilizing displacement potential function of the infinite body under single force, distribution of axial stress on anchoring body and surrounding rock is theoretically deduced; and additive axial stress on anchored section is calculated under some prestress. Based on the state of additive axial stress and dynamic stress, stress condition of rockbolt is analyzed.

Key words: grouted rockbolt, model test, blast loading, axial stress wave, prestress