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On Mutual Dynamic Effect of Tunnel Blasting Construction Adjacent to Existing Tunnel
(1 School of Civil Engineering, Henan Polytechnic University, Jiaozuo 454000; 2 College of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454000)
Abstract Construction of the new tunnel could result in deformation and even damage of the surrounding rocks and lining structures of existing tunnel when two tunnels are very close. Taking a large-span highway tunnel approaching a small existing tunnel as the background, LS-DYNA explicit dynamic numerical simulation method is adopted to study mutual effect of tunnel blasting construction adjacent to existing tunnel. The results show that the vibration velocity component in the new tunnel is perpendicular to the tunnel contour and the horizontal component of the vibration velocity at the existing tunnel side facing the blasting is the largest; the effect of surrounding rock type on blasting vibration velocity is mainly at the new tunnel side approaching the existing tunnel and it has little effect on the vibration velocity in the existing tunnel; the explosive dosage and tunnel span have significant effect on the new tunnel floor near the blast source and the clear distance has large effect on the new tunnel at the side approaching the existing tunnel; explosive dosage increase, reduction of clear distance and span will cause increase of the vibration velocity of the existing tunnel to certain extent; regardless of the relative position of two tunnels, the maximum vibration velocity of the new tunnel occurs at the side approaching the existing tunnel, the maximum vibration velocity of the existing tunnel occurs at the side facing the blasting, and the vibration caused by blast which working face passes through above the existing tunnel is larger than that which the working face is far away from the existing tunnel;the existing tunnel has certain amplification effect on the vibration velocity of the new tunnel.
Abstract：
Construction of the new tunnel could result in deformation and even damage of the surrounding rocks and lining structures of existing tunnel when two tunnels are very close. Taking a large-span highway tunnel approaching a small existing tunnel as the background, LS-DYNA explicit dynamic numerical simulation method is adopted to study mutual effect of tunnel blasting construction adjacent to existing tunnel. The results show that the vibration velocity component in the new tunnel is perpendicular to the tunnel contour and the horizontal component of the vibration velocity at the existing tunnel side facing the blasting is the largest; the effect of surrounding rock type on blasting vibration velocity is mainly at the new tunnel side approaching the existing tunnel and it has little effect on the vibration velocity in the existing tunnel; the explosive dosage and tunnel span have significant effect on the new tunnel floor near the blast source and the clear distance has large effect on the new tunnel at the side approaching the existing tunnel; explosive dosage increase, reduction of clear distance and span will cause increase of the vibration velocity of the existing tunnel to certain extent; regardless of the relative position of two tunnels, the maximum vibration velocity of the new tunnel occurs at the side approaching the existing tunnel, the maximum vibration velocity of the existing tunnel occurs at the side facing the blasting, and the vibration caused by blast which working face passes through above the existing tunnel is larger than that which the working face is far away from the existing tunnel;the existing tunnel has certain amplification effect on the vibration velocity of the new tunnel.
YU Jianxin1 LIU Huanchun2 WEI Haixia1 CHEN Chen2
.On Mutual Dynamic Effect of Tunnel Blasting Construction Adjacent to Existing Tunnel[J] MODERN TUNNELLING TECHNOLOGY, 2019,V56(6): 85-92
2019, Vol. 56 