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基于数值模拟的岩石巷道深孔分段装药掏槽爆破研究

Research on deep hole segmented charge cut blasting of rock roadway based on numerical simulation

  • 摘要: 随着炮孔深度增加,炮孔底处岩石夹制作用增强导致破岩效率和炮孔利用率较低,原有的连续装药方式不能解决上述问题。在这个基础上,研究了岩石巷道深孔分段装药掏槽爆破技术来提升掏槽爆破效率。使用光滑粒子流体动力学−有限元方法(SPH-FEM)建立了不同分段装药结构的单孔掏槽爆破模型,分析了不同模型爆破过程中岩石粒子抛掷速度、岩石抛掷数量以及爆破腔体特征。结果表明:不同装药结构会影响炮孔附近岩石的损伤范围,传统的连续装药结构在炮孔径向形成的损伤区域比分段装药结构大。此外,连续装药结构由于炸药集中在炮孔底部使得炸药能量分布不均匀,导致掏槽爆破效果差;采用分段装药结构可以增加岩石破碎数量和优化爆破腔体,岩石粒子在飞散过程中会产生2次加速现象;第一段装药比例较大或者较小会明显造成炸药能量利用不合理以及爆破腔体效果差。在模拟中设定的炮孔长度、岩石参数以及炸药性能条件下,当第一段装药比例为0.4时,深孔岩石巷道掘进掏槽爆破能够充分利用炸药能量,达到较好的掏槽爆破效果。将数值模拟得到的最优分段比例应用到现场巷道掘进爆破施工中,并利用数码电子雷管实现掏槽孔内2段炸药的延时起爆。现场试验结果表明分段装药能够在深孔掏槽爆破中创造良好的爆破效果以及提高炮孔利用率。

     

    Abstract: With the increase of the depth of the blast hole, the rock clamping effect at the bottom of the blast hole is enhanced, resulting in low rock breaking efficiency and blast hole utilization. The past continuous charging method can not solve the above problems. On this basis, this paper studies the rock roadway deep hole segmented charging cut blasting technology to improve the cut blasting efficiency. Using the smooth particle hydrodynamics-finite element method (SPH-FEM), a single-hole cut blasting model with different segmented charge structures was established, and the blasting speed of rock particles in the rock, the number of rock blasting and the characteristics of blasting cavity were analyzed in the blasting process under different models. The results show that different charge structures affect the damage range of the rock near the blast hole, and the damage area of the traditional continuous charge structure in the direction of the blast hole is larger than that of the segmented charge structure. In addition, the continuous charge structure makes the energy distribution of the explosive uneven because the explosive is concentrated at the bottom of the blast hole, resulting in poor blasting effect. The segmented charge structure can increase the number of rock fragments and optimize the blasting cavity, and the rock particles accelerate twice in the process of flying. The large or small proportion of the first segment charge obviously causes the unreasonable use of explosive energy and the poor effect of blasting cavity. Under the conditions of blast hole length, rock parameters and explosive performance set in the simulation, when the first stage charge ratio is 0.4, deep-hole rock tunnel excavation and blasting can make full use of explosive energy to achieve better cut blasting effect. The optimal subsection ratio obtained by numerical simulation was applied to the blasting construction of roadway excavation, and the delay initiation of two explosives in the cut hole was realized by using digital electronic detonator. The field test results show that the segmented charging can create good blasting effect and improve the utilization rate of blast holes in deep hole cut blasting.

     

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