菱形楔形混合掏槽爆破的数值模拟研究与应用

Numerical Simulation Research and Application of Diamond and Wedge-shaped Cutting Blasting

为了提高隧道在坚硬岩石条件下深孔爆破的掘进效率,首先提出了菱形楔形混合掏槽技术,计算了掏槽爆破技术参数;然后采用数值模拟研究了混合掏槽的爆破成腔过程及应力波的传播规律,实现了槽腔过程的可视化,并提取了关键部位的有效应力峰值;最后进行了现场应用试验。研究表明:该掏槽方式形成了多级多段掏槽,增加了爆炸应力波对坚硬岩体拉伸压缩破坏的次数,有利于破碎坚硬岩石;菱形掏槽炮孔侧面单元的有效应力峰值上下波动小,能量分布平均,能减弱炮孔过长引起的岩石夹制作用,形成稳定成型的槽腔;经测试,平均炮孔利用率达到了94%,验证了菱形楔形混合掏槽爆破参数的合理性。

In order to improve drivage efficiency of deep hole blasting in hard rock tunnels, a diamond and wedge-shaped cutting blasting technology was firstly put forward and the cutting blasting parameter was calculated. Hence, the cutting cavity formation can be visualized after adopting numerical simulation by studying the mixed cutting cavity shaping process and the spreading of stress wave, meanwhile the effective stress peak was drawn from key parts. Finally the spot application tests were carried out. All the results show that the diamond and wedge-shaped cutting is much appropriate in smashing hard rocks due to multilevel and multi-section cuttings which can produce larger blasting stress after many stretches, compresses and breaches on hard rocks. The effective stress peak on profile of the diamond wedge-shaped cutting groove hole fluctuates tiny and the energy distribution averages well, which reduces the clamping and pressing influence caused by lengthy blasting holes and forms a stable cutting cavity. The result proves that the blasting parameter of diamond wedge-shaped mixed cutting is reasonable, and the blasting holes＇ average utilization reaches 94%.