小秦岭井巷工程岩爆控制试验

 有岩爆倾向岩石遇到较高的支承压力时常发生岩爆.为了控制岩爆,依据支承压力分布规律,借助钻孔受压变形释放部分集中应力,并借助爆破震动引起支承压力峰值向岩体深部转移而增加减压区的承载能力.现场爆破试验得到了巷道、马头门和竖井掘进的岩爆控制施工参数及防范卡钻的措施.试验表明：超深钻孔与掘进进尺的比例达到2~3时可成功控制掘进端面的岩爆,呈三角形布置超深钻孔可成功控制巷道、马头门及竖井掘进的端面岩爆,间隔1.5~2.5m布置深2.0~3.0m的震动炮孔可以成功控制巷道帮墙或竖井井壁的岩爆,光面爆破或台阶光面爆破成巷并临时锚杆支护码头门能避免冒顶或片帮.

Field Tests on Rock Burst Control of Shafts and Tunneling Engineering in Xiaoqinling Mountain

Rock burst often occurs when burst-prone rocks meet higher bearing pressure. In order to control the rock burst, based on the distribution of bearing pressure, the borehole deformation and blasting vibration are used in order to shift the peak bearing pressure to the deep rock mass, and to release some concentrated stress, therefore to increase the carrying capacity of decompression zone. Construction parameters controlling rock burst and the prevention measures for the drilling tool from jamming are obtained by using the field burst tests on tunnel, ingate, and shaft excavation. Test results show that it could successfully control the rock burst at the front end, when the ratio of crossing over cycle to excavation depth reaches at 2~3. And a triangular arrangement of super-deep hole is able to resoundingly control the rock burst in tunnel, ingate and shaft excavation face. In addition, the interval of 1.5~2.5m layout plus the deep vibration hole of 2.0 ~3.0m is able to successfully control the rock burst in the tunnel waist wall or in the wall of a shaft well. And then smooth blasting or bench smooth blasting with temporary rock bolting is able to avoid roof fall or wall caving in the ingate.