单向初始荷载下爆破漏斗破坏效应试验研究

Experimental Study on Destruction Effect of Blasting Crater Under Unidirectional Initial Load

深井矿山通常面临着高地应力开采环境,同时高地应力反作用于爆破破岩过程。为研究单向初始荷载对爆破漏斗破坏的影响规律,分析了初始荷载对爆生裂隙的影响机制,并进行了侧向爆破模型试验及数值模拟分析。研究表明:外加初始荷载对爆破裂隙范围的影响程度取决于爆炸荷载大小和岩石力学参数,岩石裂隙区主要受控于拉伸应力与抗拉强度的关系;在裂隙区范围内,距离炮孔中心越近,外加荷载对裂隙的影响越小;在混凝土爆破模型应力—应变曲线的弹性变形阶段范围内时,外加初始荷载对爆破效果表现出一定的抑制作用;相比于无荷载状态,5 MPa和10 MPa下的炸药单耗分别增大了35.80%和90.12%,而外加荷载为10 MPa时的K50、K80值分别降低了1.65%和0.44%,说明初始荷载在一定程度上也可以降低爆破大块率,有利于改善爆破块度分布。数值模拟结果与模型试验结果具有很好的一致性,研究结果对于深井开采爆破参数优化具有一定的理论指导作用。

Deep mines are usually faced with high ground stress mining environment,and high ground stress reacts to the process of rock blasting.In order to study the influence of unidirectional initial load on the blasting crater,the influence mechanism of initial load on blasting cracks was analyzed,and then the lateral blasting model tests and numerical simulation analysis were carried out.The results indicated that the degree of influence of the initial loaddepends on the magnitude of the explosion load and rock mechanical parameters.And the rock fissure zone was mainly controlled by the relationship between tensile stress and tensile strength.Within the range of the rock fissure zone,the closer to the center of the blasthole,the smaller the effect of the applied load on the fissure.When within the elastic deformation stage of the stress-strain curve of the concrete model,the initial load showed a certain inhibitory effect on the blasting effect.Compared with the no-load state,the unit consumption of explosives at 5 MPa and 10 MPa increased by 35.80%and 90.12%.And the K50and K80at an initial load of 10MPa could be reduced by 1.65%and 0.44%,respectively,indicating that the initial load could also reduce the blasting block rate to a certain extent,which was beneficial to improve the blasting block distribution.The numerical simulation results were in good agreement with the model tests,the research results have certain theoretical guiding role in optimizing the blasting parameters for deep mining.