Displacement responses of Dahuanggou surrounding rock with small clearance under blast loads

Based on the blasting vibration monitoring data of Dahuanggou highway tunnels from Dandong to Tonghua, the FLAC-3D software was used to analyze the displacement responses of Dahuanggou tunnel surrounding rock with small clearance under blast loads. According to the monitoring data of the blasting vibration particles，the displacement responses of the surrounding rock, of which the left and right tunnels were subjected to circular blasting excavation with six times in all, were simulated by considering the coupling effect of the vertical and horizontal particle vibrations. And the acoustic wave velocities of the surrounding rock were experimentally measured. The simulated results were compared with the measured results. Comparisons show that with the progress of the circular blasting excavation, the surrounding rock is stable, and the damage and displacement offset of the surrounding rock take on certain symmetry by taking the middle column as an axis and getting rid of the effects of the blast load sequence undergone by the left and right tunnels. And with the progress of the blasting excavation, the distances of the monitoring points away from the explosion center increase, the blastinduced stress waves weaken at the monitoring points, the fatigue damage and displacement offset increment of the surrounding rock decrease and it tends to a stable state eventually.