孔底空气间隔装药空气层最佳比例确定方法

Determination of optimal explosive air ratio for borehole bottom interval charging

针对某露天煤矿生产爆破中存在的振动过大的问题,引入孔底空气间隔装药技术,为了确定最佳空气层比例,运用非线性动力分析软件LS-DYNA分别对耦合装药、孔底空气层比例10%和孔底空气层比例20%台阶爆破进行数值模拟,最大主应力时程曲线表明间隔装药可以有效地降低应力峰值并延长爆破荷载作用时间,通过减振率结合最大主应力法分析,得出适合该工况的最佳空气比例为20%,扩充了轴向间隔装药最佳空气层比例确定方法。

Aimed at large vibration during blast for coal production in open--pit coal mine, the technique of interval charging with air at the bottom of borehole was introduced. In order to determine the optimal air ratio, the nonlinear dynamic analysis software LS-DYNA was used to simulate the bench blasting under coupling charging, with air ratio of 10% and 20% at the bore- hole bottom. The time-history curve of maximum principle stress showed that the interval char- ging could effectively decrease stress peak and prolong blasting load time. The optimal air ratio is 20% for this operation condition according to vibration reduction rate and the maximum principle stress, expanding the determination method of optimal air ratio for interval charging in axial di- rection.