煤矿火烧岩爆破破碎机理及爆破参数优化

Blasting fragmentation mechanism and blasting parameter optimization of coal mine burned rock

针对煤矿火烧岩台阶爆破效果不理想问题,通过理论分析、数值模拟、实验室实验与现场试验相结合的方法,以大南湖二号露天煤矿为例,研究火烧岩的物理力学特性、爆破破碎机理以及影响爆破的因素,优化爆破参数。研究表明:岩体在高温作用后强度变低、易破碎、裂隙极发育。爆破时,若裂隙方向与应力波传播方向平行,会产生应力集中现象;若裂隙方向与应力波传播方向不平行,则在裂隙处会发生应力波反射与折射现象,缩短应力波作用时间,加剧炮孔周围岩体的破碎程度。采用泥浆护孔能够提高火烧岩台阶的成孔率,结合火烧岩爆破破碎机理优化爆破方案,通过现场爆破试验,验证了优化后爆破参数的适用性。

In order to solve the problem of unsatisfactory bench blasting effect of burnt rock in coal mine,through the combination of theoretical analysis,numerical simulation,laboratory experiment and field test,taking Dananhu No.2 open-pit coal mine as an example,the physical and mechanical properties of burnt rock,the mechanism of blasting fragmentation and the factors affecting blasting are studied,and the blasting parameters are optimized.The research shows that the strength of rock mass becomes low and easy to break after high temperature,and the cracks in rock mass are very developed.When blasting,if the crack direction is parallel to the stress wave propagation direction,the stress concentration phenomenon will occur.If the fracture direction is not parallel to the propagation direction of stress wave,the reflection and refraction of stress wave will occur at the fracture,which will shorten the action time of stress wave and aggravate the fragmentation degree of rock mass around the borehole.The use of mud to protect the hole can improve the hole forming rate of the incendiary rock step.The blasting scheme is optimized in combination with the blasting crushing mechanism of the incendiary rock.The applicability of the blasting parameter optimization is verified by the field blasting test.