分岔段超小净距隧道爆破围岩振动衰减特征

Characteristics of vibration attenuation in wall rock by tunnel blasting at the fork section of super-close-spacing

为研究隧道分岔段控制爆破振动对相邻隧道的影响,根据大量现场振动监测数据,分析论证了掏槽爆破和预留光爆层爆破对前方相邻隧道和后方中隔岩墙的振动影响,发现后方中隔岩墙的爆破振动比前方放大1.4倍左右;并根据振动波形分析,论证了高段位雷管的延时误差和临空面条件对降低爆破振动的影响,从而提出了“尽量减小掏槽爆破的单段药量,MS7段以上雷管不需跳段使用,根据振动波形适当增大高段位雷管的炮孔数”,这些技术措施可以显著降低爆破振动、提高爆破进尺,可为同类爆破提供借鉴。

In order to study the influence of the control blasting vibration in the tunnel fork section on the adjacent tunnel,based on a large number of field vibration monitoring data,the influence of cutting blasting and smooth blasting of the preserved layer on the adjacent tunnel in front and the rear partition rock wall is analyzed and demonstrated.It is found that the blasting vibration of the rear partition rock wall is about 1.4 times larger than that of the front.According to the vibration waveform analysis,the influence of delay error of high delay-number detonator and the condition of free surface on reducing blasting vibration is demonstrated.It is proposed“to minimize the explosive charge among delay groups of cutting blasting as far as possible,not to skip delay numbers while using detonators above MS7,and increase the blasting holes with high delay-number detonators appropriately according to the vibration waveform”.These technical measures can significantly reduce blasting vibration and increase blasting footage,which could provide a reference for similar blasting operations.