留巷切顶聚能爆破空孔效应研究及应用

Research and application of empty hole effect of roof cutting energy-gathering blasting in retaining roadway

本文以常村矿2303回风巷道为工程背景,进行留巷切顶聚能爆破空孔效应研究,结合弹性力学理论建立空孔效应力学模型,确定聚能爆破在爆破孔与空孔连线的垂线方向实现最大拉应力,聚能爆破工艺通过增加聚能药包、定位块等装置,较传统切顶爆破,能实现更好的预裂效果,经过多方案数值模拟验证分析,确定空孔能够显著改变空孔附近有效应力状态,且距离空孔越近爆破效果越明显,空孔能够有效增加主裂缝扩展长度,进而增大爆破孔距离,通过综合分析爆破预裂效果,确定空孔作用下爆破孔合理间距为800 mm。

No.2303 return air roadway of Changcun Mine was taken as the engineering background to study the empty hole effect of roof cutting blasting in retaining roadway.Combined with the theory of elastic mechanics,the mechanical model of empty hole effect was established.It was determined that the maximum tensile stress could be realized in the vertical direction of the connection between the blasting hole and the empty hole.The energy-gathering blasting process achieved better pre-splitting effect than the traditional roof cutting blasting by adding energy-gathering charge,positioning block and other devices.Through the verification and analysis of multi-scheme numerical simulation,it was determined that the empty hole could significantly change the effective stress state near the empty hole,and the closer to the empty hole,the more obvious the blasting effect was.The empty hole could effectively increase the extension length of the main crack,and then increased the distance of the blasting hole.Through the analysis of blasting pre-splitting effect,the reasonable spacing of blasting holes under the action of empty holes was determined to be 800 mm.