摘要 |
The bond integrity of resin grouted rock bolts or roof bolts anchored within the ceiling in underground mines is tested by inducing broadband vibrations and measuring the resonant frequencies of the axial and transverse vibration modes. Voids in the resin grout or imperfect bonding cause shifts in the resonant frequencies. The tension in expansion nut rock bolts is determined from the resonant frequency of the transverse vibration mode. |