深埋岩石隧洞的周边控制爆破方法与参数确定

The controlled contour blasting technique and its parameter determination for rock tunnel at depth

利用弹性理论方法,结合周边控制爆破的炮孔间贯通裂纹形成机理分析了原岩应力对光面爆破和预裂爆破炮孔间贯通裂纹形成的影响。结果为:原岩应力的存在有利于光面爆破的炮孔间贯通裂纹的形成,不利于预裂爆破的炮孔间贯通裂纹的形成。由此得出结论:高原岩应力条件下的隧洞开挖周边控制爆破宜采用光面爆破方法,光面爆破参数需要根原岩应力、隧洞开挖半径和岩石力学性质进行相应调整。对高原岩应力条件的隧洞开挖实施预裂爆破时,应采用岩石定向断裂爆破技术。

Effects of residual stress on the formation of crack coalescence between sequent shot-holes in smooth blasting and pre-split blasting are analyzed based on the elastic theory. Results indicate that the residual stress is useful to form the cracks between the shot-holes for smooth blasting, but not for pre-split blasting. For smooth blasting, the parameters of blast have to be adjusted according to the residual stress, the tunnel radius, and the mechanical property of the rock. In the case of pre-split blasting, the controlled directional blasting should be considered.