坚硬顶板深孔预裂爆破参数优化数值模拟研究

深孔预裂爆破是弱化坚硬顶板的一种有效方式,预裂爆破参数的选择对顶板弱化效果有很大影响。以山西某矿22205厚煤层坚硬顶板综放工作面的具体工程地质条件为背景,采用基于Hoek-Brown强度准则的岩体深孔预裂爆破影响区等效连续力学参数估算方法,运用FLAC3D软件建立了坚硬顶板深孔预裂爆破的三维数值计算模型,研究了不同的爆破孔距开切眼距离、爆破孔深度等关键参数对坚硬顶板初次来压的影响规律。在此基础上,合理设计优化了22205综放工作面坚硬顶板的深孔预裂爆破方案与参数,并进行了现场工程实践。现场矿压监测结果表明,采用深孔预裂爆破技术后,坚硬顶板的初次来压步距减小了约20m,显著改善了坚硬顶板来压期间的安全状况,保障了工作面的正常安全生产。

Numerical simulation on parameters optimization of deep-hole pre-splitting blasting of hard roof

Deep-hole pre-splitting blasting is an effective way to weaken the hard roof, but the selection of pre-splitting blasting parameters has a great influence on the roof weakening effect. A fully mechanized top coal caving face with hard roof in 22205 thick coal seam of a coal mine in Shanxi Province was selected the specific research background. An equivalent continuous mechanical parameters estimation method of rock mass after pre-splitting blasting was proposed based on Hoek-Brown strength criterion, and a three dimensional numerical model of deep-hole pre-splitting blasting of hard roof was established by using FLAC3D software. The effects of key parameters such as the distance between the blasting hole and the cutting hole and the depth of the blasting hole on the first roof weighting interval of the hard roof were studied. On this basis, the deep-hole pre-splitting blasting schemes and parameters of the hard roof of 22205 fully mechanized top-coal caving face were reasonably proposed and optimized, and the field engineering practice was carried out. The in-site mine pressure monitoring results showed that after adopting the deep-hole pre-splitting blasting technology, he first roof weighting interval of the hard roof was reduced by about 20m, which significantly improves the safety condition during the hard roof pressure and ensures the normal and safe production of the working face.