Dynamic Response Analysis of Underground Double-Line Tunnel under Surface Blasting

Blasting has been widely used for economical and rapid rock excavation in civil and mining engineering. In order to study the influence of relative horizontal distance and relative vertical distance between two tunnels on the dynamical response of the two tunnels, 10 numerical simulation cases are done by LS-DYNA 3D models under surface explosion by controlling the clear distance and height difference of double-line tunnel, and the ALE multimaterial fluid structure coupling algorithm is applied to analyze the dynamic response characteristics of double-line tunnel under different conditions. The numerical results show that the dynamic response characteristics of the tunnel lining are affected by the change of the clear distance and height difference of the tunnel. With the increase of the height difference between adjacent tunnels, the peak value of vibration velocity at the top of the lining on the blast face increases, which is due to the upward elevation of the right tunnel, which is more conducive to the reflection and superposition of stress waves. When the height difference of tunnel is 4–6 m, the vibration velocity and displacement of monitoring point C on the back blasting side will change abruptly, and the variation range of vibration velocity is about 25%, while the variation range of displacement is about 60%.