金属介质在切割爆破中的定向作用

Directional effect of metal medium in joint cutting blasting

为了研究定向切割中金属介质对爆炸能量传播的控制作用,采用理论计算和LS-DYNA数值模拟软件分析了孔壁初始裂缝的形成和裂缝贯穿的机理。结果表明:由于金属介质的冲击阻抗远大于水介质,沿金属介质方向传播的爆炸压力和速度都远大于其他方向,导致金属介质接触的孔壁处首先产生初始裂缝,随后在爆轰压力和"水楔"作用下裂缝失稳贯穿。有机玻璃模型实验结果表明:受金属介质的控制,模型能按照预定方向断裂出平整光滑裂缝,炮孔周围仅有少数短裂隙,证明了该技术的优势。

To study the control function of metal medium on the explosion energy transmission in directional cutting blasting ,theoretical calculation and numerical software of LS-DYNA were used to analyze the mechanism of initial crack formation and crack penetration in the blasthole wall. The results indicated that the explosion pressure and velocity spread in the direction along metal medium was higher than other directions because shock wave impedance of metal medium was larger than impedance of water medium. The initial crack firstly appeared in the blasthole wall contacted with the metal medium. Then, the cracks were unstable and penetrated under the action of detonation pressure and water wedge. The PMMA model test results indicated that the model could be cut to form seams according to the predetermined direction under the effect of the metal medium. There were only a few short cracks around the blasthole.