分幅减振爆破开挖技术实践

Practice of excavation blasting technology with the separate reduce vibration

为解决在某石油储库顶部拱形岩巷施工过程中存在爆破振动过强、掏槽效果不佳、炮孔利用率不高、壁面成型不良且周边孔半孔率不足70%及围岩损伤过大等问题,提出“分幅减振爆破开挖技术”的解决方案,将断面化大为小,分次爆破,有效降低单次起爆药量和最大单段药量。采用复式楔形掏槽,周边孔光面爆破,毫秒延时起爆。现场试验表明,围岩峰值振速降为13.1 cm/s,爆破振动明显减弱,炮孔利用率高达90%以上,周边孔半孔率提高到85%,壁面成型良好,改进方案爆破效果良好。分幅减振爆破在大断面硬岩钻爆掘进中体现了良好的适用性,能够实现弱振动、高效率、大进尺开挖,满足地下水封石油洞库的特殊要求,可为类似岩石地下工程钻爆开挖提供借鉴与参考。

In the process of rock tunnel construction at the top of the oil cavern project,some problems come into being,such as strong blasting vibration,poor cutting effect,low utilization rate of borehole,weak formation of excavation outline,and the remained semi void rate of contour hole is less than 70%and excessive damage of surrounding rock.Then,the vibration reduction excavation technology with the separate blasting is proposed to settle these problems,which divides large section into small section,separates left and right blasting,and decreases the single blasting charge and the maximum charge of one section effectively.The vibration reduction technology adopts duplex wedge cut,contour hole with smooth blasting and millisecond delay initiation.The field tests show that the peak particle velocity decreases to 13.1 cm/s,the blasting vibration is weaken obviously,the utilization rate of borehole reaches up to 90%,the remained semi void rate of contour hole increases to 85%,and the excavation outline forms well,the improved method gets good blasting results.The vibration reduction blasting with the separate left and right shows good applicability in hard rock excavation of large section tunnel adopting drilling and blasting method.It can meet the special requirements of underground water-sealed oil cavern,with weak vibration,high efficiency and large advance per round,and provide some reference for drilling and blasting excavation of other similar underground rock engineering.