坚硬岩石一次爆破成井掏槽方式的数值模拟研究

对坚硬岩石条件下深孔一次爆破成井的九孔、双孔菱形、单螺旋和双螺旋4种掏槽方式,在炸药爆炸荷载作用下的应力产生和传播机理进行了计算机数值模拟。模拟采用LS-DYNA三维非线性动力有限元程序,结果得到了4种掏槽方式的节点最大应力产生的时间、空孔周边应力产生的时间、有效应力作用的时间、节点最大运动速度以及掏槽孔应力全部贯穿的时间等相关参数的定量计算值。通过对计算结果的综合优化研究,选择了单螺旋掏槽方式优化模型。该研究成果,已在现场应用中得到了验证。试验结果表明,该方法解决了制约一次爆破成井相关爆破参量难以确定和爆破效果难以预料等技术上的瓶颈问题,并为其在地下建筑工程领域中推广应用提供了科学合理的理论指导依据,具有广阔的推广应用前景。

NUMERICAL SIMULATION ON CUTTING MODE OF SHAFT EXCAVATION BY ONE-STEP DEEP-HOLE BLASTING IN HARD ROCK

By using the LS-DYNA 3D nonlinear dynamic finite element software,the elasticity calculation model was established to analyze the generation and transmission of stress under explosive charge in 4 typical cutting patterns,those used in shaft excavation by one-step blasting were optimized and compared by numerical simulation to select the optimizing cutting patterns. The 4 typical cutting patterns are:9-hole cut,single-spiral-hole cut,double- spiral-hole cut,and 2-empty-hole-diamond cut. LS-DYNA 3D nonlinear dynamic finite element software was applied to simulate the shaft excavation by one-step blasting to achieve the generation and transmission mechanism of stress wave,which would be helpful for selecting the best cutting pattern. The simulation results showed that the single-spiral-hole cut was the optimum cutting pattern according to the related parameters such as the maximum generating time of stress,the generating time of stress around the empty holes,the action time of available stress,and the maximum velocity of node and the penetrating time of stress. The research results of numerical simulation have been proved by field productive application. The bottleneck problems referring to the blasting parameters in shaft excavation by one-step blasting have been solved. This research presented a scientific and reasonable theory for the underground engineering and would have the wide application prospect in the future.