并行小净距隧道楔形掏槽爆破振动效应研究

以重庆鸭江隧道小净距段爆破掘进施工为背景,采用现场振动监测与数值计算相结合的方法研究了并行小净距隧道后续洞上台阶采用楔形掏槽爆破产生的振动效应,分析了掏槽孔与掌子面之间的布置角度对振动速度场的影响。结果表明:先行洞迎爆侧边墙上的最大振动速度出现在后续洞爆破掌子面的侧后方;掏槽孔的布置角度越大则振动强度的极值越大,极值出现的位置也越靠近爆破掌子面。可以通过减小掏槽孔的布置角度来实现降低隧道掘进爆破振动强度的作用,此外在施工现场布置振动监测点时应考虑掏槽孔布置角度的影响,掏槽孔的布置角度越大则振动监测重点区域与爆破掌子面间的距离越小。

Blasting Vibration Effect of Wedge Cut Blasting in Parallel Small-distance Tunnel

Based on the blasting excavation of small-distance section in Chongqing Yajiang Tunnel, by using the method of field vibration monitoring and numerical calculation, the vibration effect caused by up bench wedge cut blasting in the subsequent hole of parallel small-distance tunnel was studied, the influence of the layout angle between the cuthole and blasting tunnel face on the vibration velocity field was analyzed. The results indicate the maximum vibration velocity of the first hole side wall facing the blasting appears on the rear blasting tunnel face; The larger the cuthole layout angle is, the greater the extreme value of the vibration intensity is, and the closer the distance of blasting tunnel face is. It could reduce the effect of the tunnel blasting vibration intensity by reducing the cuthole layout angle. The influence of the cuthole layout angle should be taken into consideration when the vibration monitoring points are arranged. The larger the cuthole layout angle is, the distance between the vibration monitoring area and the blasting tunnel face is smaller.