Application of Digital Detonator Staggered-phase Vibration Abatement Technology in Railway Tunnels with Ultra-close Spacing
(1. China Railway 18th Bureau Group Co., Ltd., Tianjin 300222; 2. School of Civil Engineering, Central South University, Changsha 410075; 3. Guiyang Public Transportation Investment and Operation Group Co., Ltd., Guiyang 550081; 4. China Railway Chengdu Group Co., Ltd., Chengdu 610082)
Abstract：
For the drainage gallery urgent remediation project of the Baiyanjiao Tunnel, where the non-blasting ex? cavation was making an extremely slow progress, the application of digital electronic detonator staggered-phase vibration abatement technology significantly improved the excavation progress and effectively controlled the impact of blasting (6.1 to 15.9 meters from the main tunnel structure) on the main tunnel. Based on four tests of continuously improved blasting schemes, the study determined the optimized design parameters of electronic detonator detonation in railway tunnels with (ultra) close spacing: the layout of double wedge-shaped cut holes followed the "symmetrical, double-layer, corresponding, confining and lifting" principles, with 0.9 kg charge for each hole and an interhole time delay of 7 minutes. It was also found that the seismic wave signal generated by the detonation of digital electronic detonator was dominated by ultra-high frequency bands (>200 Hz), and the higher the leading frequency was,the lower the vibration velocity would be. The leading frequency bands of vibration in the four blast tests showed a tendency toward a high frequency and a more even distribution, which could effectively avoid damage to the tunnel structure from low-frequency vibration.
WANG Lichuan1,
2 ZHANG Xuemin2 WU Haibao3 ZHOU Xianshun2 LIAN Fasheng4 ZHANG Peng4
.Application of Digital Detonator Staggered-phase Vibration Abatement Technology in Railway Tunnels with Ultra-close Spacing[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(3): 236-245
2022, Vol. 59 