不同耦合系数条件下岩石损伤特性的研究

在预裂爆破中,采用合理的空气比和不耦合系数能有效控制爆炸荷载对岩体的破坏。利用Autodyn有限元动力分析软件,研究预裂爆破中空气间隔不耦合装药产生的爆炸荷载对岩石的损伤特性和孔壁冲击波峰值的变化规律。通过改变装药空气比,分析空气间隔装药产生的爆炸冲击波沿孔壁的压力分布,以及间隔装药时不耦合系数对孔壁冲击波峰值和应力波传播的影响。结果表明:连续装药条件下,爆破近区的压力峰值高于岩石动态抗压强度,离炮孔越远应力波衰减的越慢;在空气间隔装药条件下,岩石的损伤深度随空气比的增大而减小,孔内空气柱周围的岩石破坏不明显;在间隔不耦合装药时,不耦合系数越大,冲击荷载的强度越低,孔壁的损伤半径也越小。

Research on damage property of rock under the condition of different decoupling coefficient

In pre-splitting blasting, the air ratio and decoupling coefficient has a great influence on the effect in pre-splitting blasting. Reasonable parameters can control the scope of failure effectively. For the dynamic property of rock under blasting load generated by air-decked decouple charge during the pre-splitting blasting, the paper research the attenuation law of the shock wave and velocity under the condition of continuous charge structure using finite element dynamic soft AUTODYN. Through change air ratio of the charge, it analyses peak value of shock wave distribution along the wall of hole. It also research the shock wave pressure and stress propagation under the influence of decoupling coefficient when discontinuous charging. The results show that in continuous charge conditions, the peak value of shock wave of the area near the blasting hole is more than the dynamic compressive strength of rock. From the hole further, the attenuation coefficient of stress wave is smaller. In air-decked charge, the damage depth is up as the decrease of the air ratio. The rock surrounding by air is not obvious failure, because the pressure of the hole wall is less than the dynamic compressive strength of rock. In discontinuous air-decked charge, the load strength and damage radius is decrease when the decoupling coefficient is increase.