浅埋隧道光面爆破减振施工技术

A Vibration-Reducing Construction Technique for Shallow-Buried Tunnels Built by Smooth-Surface Blasting Method

为降低爆破振动对城市地铁周边建(构)筑物或管线的影响,减少区间隧道超欠挖,降低围岩支护成本,以青岛地铁2号线区间隧道作为试验巷道。对掏槽及辅助孔,采取一次起爆分段延时的爆破减振技术,控制爆破振动速度。通过导爆索串联周边炮孔,实现同时起爆周边眼的隧道光面爆破技术。经现场测试,被保护物振动速度均控制在1.5cm/s以下,炮孔残留率达到90%,循环进尺提高13%,基本实现无超挖。本技术有效解决了原施工方案超挖严重、不能有效控制振动速度的问题,对同类工程有一定的借鉴意义。

In order to reduce the effect of the blasting-caused vibration on buildings and pipelines neighboring municipal subways,reduce the sectional under-cutting or over-cutting of a tunnel and decrease the cost in supporting the surrounding rock,the sectional tunnel of the Second Line of the Qingdao Subway is chosen as the test shaft for research.The blasting-vibration-reducing technique of the one-time detonation with different sectional delays is applied to the under-holed grooves and auxiliary holes,with the velocity of blasting vibration controlled.With the smooth-surface blasting technique for tunneling adopted,a series of detonating cords is used to connect all the neighboring holes in series to detonate all the holes at the same time.According to the site test,the vibration velocity of the protected objects is all kept under 1.5cm/s.At the same time,the hole residual rate reaches 90%,and the cyclical drilling footage is increased 13%.Fundamentally no over-cutting happens.This technique effectively solves the disadvantages of the original construction scheme in serious over-cutting and being unable to control the velocity of vibration.It may serve as a useful reference for other projects of the same type.