含控制孔切槽爆破的裂隙扩展机制研究

Study on crack propagation mechanism of grooving blasting with controlled hole

为了丰富切槽爆破增透理论,以期为指导切槽爆破增透实践提供理论依据,采用理论分析、数值模拟、相似模拟试验的方法对切槽爆破在含控制孔情况下的裂隙扩展机制进行研究。研究表明:控制孔作用下的切槽爆破在切槽根部会产生抑制区,切槽方向上的压应变峰值是切槽45°方向上的压应变峰值的2.77倍,是拉应变峰值的1.94倍;应力波传播至控制孔后反射成拉伸波,反射拉伸波和切槽尖端的集中应力产生叠加,促进切槽尖端裂隙的扩展。说明含控制孔的切槽爆破可以有效避免爆破裂隙的随机发育,对爆破裂隙有着良好的控制导向作用,可达到定向爆破煤岩体的效果。

In order to enrich the theory of grooving blasting enhancement and provide a theoretical basis for guiding the practice of grooving blasting enhancement,the method of theoretical analysis,numerical simulation,and similar simulation tests are used to study the crack propagation mechanism of grooving blasting with control holes.The research shows that the grooving blasting under the control hole will produce a suppression zone at the root of the grooving.The peak compressive strain in the direction of the groove is 2.77 times the peak compressive strain in the direction of 45°and 1.94 times the peak value of the tensile strain;The stress wave propagates to the control hole and is reflected as a tensile wave.The reflected tensile wave and the concentrated stress at the tip of the slot produce superposition,which promotes the expansion of the slit at the tip of the slot.It shows that grooving blasting with control holes can effectively avoid the random development of blasting cracks,and has a good control and guiding effect on blasting cracks.