小净距隧道围岩的爆破振动影响规律研究

小净距隧道后行隧道爆破施工会引发相邻先行隧道围岩振动,振动强弱与隧道净距和单次炸药量相关,通过工程现场监测和数值模拟相结合的方式,对隧道净距的影响规律展开研究。结果表明,小净距隧道后行隧道掌子面起爆时,相邻先行隧道迎爆面拱腰处围岩爆破振动速度最大,最大振速随隧道净距的增大而不断减小,随单次炸药量的增大而增大。当Q/R³＜1×10^-3时,后行隧道掌子面爆破对先行隧道围岩的爆破振动影响可忽略不计。对先行隧道围岩最大振速进行萨道夫斯基公式拟合,得到小净距隧道相邻先行隧道Ⅲ级围岩最大振速预测方程中的场地系数K=8.73,衰减系数α=0.83。

Study on the Impact of Blasting Vibration on Surrounding Rock of Small Clearance Tunnels

Blasting construction of the rear tunnel of small clearance tunnel will cause vibration of surrounding rock of adjacent preceding tunnels. The vibration intensity is related to the tunnel clearance and the single explosive charge The influence law of the tunnel clearance and the single explosive charge were studied through the combination of engineering site monitoring and numerical simulation. The results show that, when the palm face of the tunnel behind the tunnel with a small clear distance is detonated, the blasting vibration velocity of the surrounding rock near the arch waist of the blasting face of the adjacent advance tunnel is the highest, and the maximum vibration velocity decreases with the increase of the tunnel clearance, and increases with the increase of the amount of single explosive. And when Q/R＜1×10, the impact of the blasting of the tunnel face on the blasting vibration of the tunnel surrounding rocks is negligible. By fitting Sadovis formula for the maximum vibration velocity of the surrounding rock of the advance tunnel, the field coefficient K=8.73 and attenuation coefficient α=0.83 in the prediction equation of the maximum vibration velocity of the Ⅲ surrounding rock of the adjacent tunnel with small clear distance tunnel are obtained.