无煤柱自成巷切顶高度与切顶角度参数研究

Study on Parameters of Cutting Height and Cutting Angle in Self-formed Roadway Without Coal Pillar

无煤柱自成巷的关键技术在于控制聚能预裂爆破的切顶高度与切顶角度,在理论层面上对比分析了传统非聚能爆破与聚能爆破的作用机理及裂纹扩展范围。以郭屯煤矿4306工作面为案例,通过UDEC软件模拟了不同切缝高度和切缝角度对顶板垮落形态与支承压力演化趋势的影响。结果表明:聚能预裂爆破的优势在于有效控制了应力波的传播方向,增加了能量利用效率。增大切顶高度可以增加采空区矸石对顶板的支撑效果,但会增加对巷道顶板的力学传递作用。增加切缝角度有利于顶板垮落,但对巷道的封闭性较差。同时指出切顶高度越高,巷道围岩卸压程度越好,切顶角度与顶板卸压效果无明显关系。

The key technology of self-forming roadway without coal pillar is to control the cutting height and cutting angle of shaped charge presplit blasting.The mechanism of action and crack propagation range of traditional non-shaped charge blasting and shaped charge blasting are compared theoretically,according to Guotun mining coal 4306 working face,and the effects of different cutting height and cutting angle on roof caving morphology and evolution trend of abutment pressure are simulated by UDEC software.The results show that the advantage of shaped charge presplit blasting is to effectively control the propagation direction and utilization efficiency of stress waves.Increasing the cutting height can increase the supporting effect of goaf gangue on the roof,but increase the mechanical transfer effect on the roadway roof.The increase of cutting angle can be beneficial to roof collapse but has poor sealing property to roadway.At the same time,it is pointed out that the higher the cutting height,the better the pressure relief degree of the roadway surrounding rock,the angle of cutting the roof has no obvious relationship with the pressure relief effect of the roof.