立井大直径中空孔直眼掏槽爆炸应力场数值模拟分析与应用

 为提高立井井筒坚硬岩石段掘进施工的爆破效率，设计在两阶同深桶形直眼掏槽中心布置一个直径100 mm的空孔。根据理论计算和工程实践经验选定掏槽爆破参数，一阶掏槽孔圈径1 700 mm、间距850 mm，二圈掏槽孔圈径2 500 mm、间距650 mm。运用有限元软件LS-DYNA对一阶掏槽孔爆破后的爆炸应力场进行数值模拟分析和爆破参数合理性验证。模拟结果表明：增加的中心大直径空孔能够提高爆炸应力波峰值和延长作用时间，空孔周围岩体中应力波峰值为无空孔时的2.2倍。同时，数值模拟还更直观地表现直眼掏槽时爆炸应力波在空孔处的应力叠加和反射拉伸现象、以及空孔具有的导向作用。在此基础上，进行立井坚硬岩石段掘进深孔爆破现场试验研究，取得在坚固性系数f = 12～17的岩石中平均炮眼利用率达91.7%、爆破块度均匀的良好效果。

NUMERICAL ANALYSIS AND APPLICATION OF LARGE DIAMETER CAVITY PARALLEL CUT BLASTING STRESS FIELD IN VERTICAL SHAFT

For improve drilling and blasting excavation efficiency of vertical shaft hard rock section，design a large diameter cavity in center of same deep of two section parallel cut blasting. According to theoretical calculation and practical experience choose cut blasting parameters，circle diameter of the first section cut hole is 1 700 mm and it?s hole space is 850 mm，the second section cut hole circle diameter is 2 500 mm with hole space 650 mm. Finite element software LS-DYNA is used for blasting stress field of first section cut blasting numerical simulation analysis and blasting parameters rationality verification. The numerical simulation results show that large diameter cavity in center can improve stress peak value and extend action time，stress wave of rock around large diameter cavity is 2.2 times than the value of rock without cavity. At the same time，numerical simulation show stress wave superposition and reflection，guiding phenomena during large diameter cavity of parallel cut. Then deep-hole blasting field research for vertical shaft hard rock section is done，obtained good effect of average utilization rate 91.7%，lumpiness uniform in rock stability coefficient f = 12–17.