空区隐患爆破治理方案及延期时间的数值模拟分析

为了防止矿山空区引起地表塌陷造成建构（筑）物的破坏以及降低矿柱塌落振动对井下开采的威胁，采用现场试验与数值模拟相结合的方法，优选爆破治理方案和延期时间。根据炮孔布置和爆破参数，建立实际比例数值模型；在岩石物理力学指标测试的基础上，确定模型材料参数；采用LS-DYNA数值模拟软件，对比分析方案优劣以及确定爆破延期时间。研究结果表明:在满足空区隐患爆破治理效果的前提下，同一节点处A方案质点振速峰值为0.923 9 m/s小于B方案质点振速峰值1.225 3 m/s；而且当延期时间为100 ms时，通过模型垂直方向的位移云图可知岩石的破坏范围最大，塌落区域更加分散。现场应用结果显示空区隐患治理工程爆破效果良好，形成了隔离缓冲层，可以保证露天和井下的安全。

Numerical simulation analysis of blasting treatment scheme and delay time for hidden trouble in goaf

In order to prevent the surface collapse caused by the mine goaf from destroying the structures and reduce the threat of pillar collapse vibration to the underground mining, the blasting treatment scheme and the delay time were optimally selected by using the combined method of field test and numerical simulation. According to the layout of blasting holes and parameters, an actual proportional numerical model was established. On the basis of measuring the physical and mechanical indexes of rock, the material parameters of the model were determined. The advantages and disadvantages of the schemes were compared and analyzed, and the blasting delay time was determined by using the LS-DYNA numerical simulation software. The results showed that on the premise of satisfying the blasting treatment effect for hidden trouble of goaf, the particle vibration velocity peak value of scheme A was 0.923 9 m/s, which was less than that of scheme B as 1.225 3 m/s at the same node. When the delay time was 100 ms, the displacement nephogram in the vertical direction of the model indicated that the rock damage range was wider and the collapse area was more dispersed. The field application results showed that the actual blasting effect of treatment project for hidden trouble of goaf was good, And the isolation buffer layer was formed, which could ensure the safety of the open pit and underground mine.