摘要
为合理解决邻近既有建(构)筑物隧道爆破开挖中降低爆破振动强度与确保施工效率之间的矛盾,基于隧道开挖时常用的楔形掏槽方式,文章优化提出了适用于中软岩隧道开挖的减震爆破技术——楔形分段毫秒延迟掏槽爆破技术。此技术借助掏槽炮孔内实行间隔分段装药结构及毫秒延迟起爆技术,确保掏槽腔体由外及内分次分层形成,以达到有效减震和获取良好爆破进尺的目的。文章在详细分析楔形分段掏槽爆破中岩体破碎和减震机理的基础上,基于微差爆破和应力波传播理论提出了影响楔形分段掏槽爆破减震和掏槽效果的掏槽深度比、段间装药分配比、炮孔倾角和段间延迟时间等关键技术参数的确定方法,并应用于指导开展现场隧道爆破试验的参数设计。现场爆破试验结果表明:楔形分段毫秒延迟掏槽爆破技术是一种既能有效降低爆破振动强度又能确保隧道施工速率的技术措施;与常规楔形掏槽爆破技术相比,此技术可将掏槽爆破产生的振动强度降低30%以上,并可获得良好的爆破进尺与效果。
In order to solve the contradiction between blast-induced vibration absorption and construction efficien- cy of tunnels approaching existing buildings by the drill and blast method, an optimized vibration absorption blast- ing technique named staged wedge-cut millisecond delayed blasting technology is developed, which is appropriate for tunnels in medium or soft rock masses. Specifically, it makes use of segmented alternative charging structures and millisecond delayed blasting technology to guarantee the formation of a cut cavity in a hierarchical way from the outside in and achieves the goals of effective vibration absorption and a good advance rate. Based on a detailed anal- ysis of the mechanism of rock breaking and vibration absorption during staged cut blasting and theories of millisec- ond blasting and stress wave propagation, the determination method for the key parameters affecting vibration ab- sorption and cut effect is proposed （such as the cut depth ratio, the distribution ratio of segmented charging, the dip angle of the cut hole and the delayed time for each segment） and applied to the parameter design for the tunnel blast- ing test at the site. The site blasting test indicates the new staged wedge-cut blasting technique can effectively re- duce the blasting-induced vibration by more than 30%, guarantee construction speed, and obtain a good advance rate and effect compared with the conventional cut blasting method.
出处
《现代隧道技术》
EI
CSCD
北大核心
2017年第4期186-192,共7页
Modern Tunnelling Technology
基金
乌鲁木齐市应用开发研究计划项目(Y131320008)
关键词
隧道工程
楔形分段掏槽
毫秒延迟
爆破振动
Tunnelling
Staged wedge-cut blasting
Millisecond delay
Blasting-induced vibration
