Experimental study and application of medium‐length hole blasting technique in coal‐rock roadway

In this study, mechanical mechanism analyses of hole cut blasting and in situ hole cut blasting tests using different cutting programs were conducted to investigate the hole cut blasting mechanism under the influence of complicated geological conditions and its blasting excavation effect. The hole cut blasting mechanism was evaluated under the background of medium‐length hole cut blasting test in a typical coal‐rock roadway in Xiayukou coal mine of Hancheng mining area in Western China to improve the blasting excavation efficiency in coal mine roadways. Test results indicated that the rock clamping action is remarkably enhanced when the depth of medium‐length holes, which are impacted by various complicated geological factors, reaches more than 1.8 m under weak coal‐rock mass conditions. At the same time, the antidrag effect is good when double‐wedge cut blasting is selected, and its mitigation of rock clamping action is reflected through the reduction of rock resistance of phase I hole cut blasting. The enhanced blasting effect is embodied by the footage cycle and forming effect of blasting, and the footage cycle of single blasting increases from 1.6 to 2.0 m, thereby indicating its remarkable economic benefits. The results of this study can provide a reference for hole cut blasting design and mechanism study of weak coal‐rock masses under complicated geological conditions.