含节理岩体爆生裂纹扩展的动焦散模型实验研究

Dynamic Caustics Model Experiment of Blasting Crack Propagating on Joint Rock

应用动态焦散线测试系统,模拟含节理岩体断裂爆破过程,进行了PMMA模型透射式动态焦散线实验,着重研究了爆炸初始裂纹与节理面不同夹角的情况下,裂纹尖端动态应力强度因子的变化规律,裂纹穿过节理面的扩展规律,以及裂纹扩展速度的变化规律。实验结果分析表明,爆生裂纹穿过节理面时,裂纹尖端的动态应力强度因子和裂纹扩展速度显著下降,穿过节理面后,应力强度因子又有所增强;裂纹穿过节理面时,裂纹会沿节理面偏离一段距离后沿初始裂纹方向继续扩展。研究结果可以为节理岩体的断裂爆破提供理论依据。

The blasting processes of rock with joints, which had different separation angles between the initial crack and joint plane, were studied using the dynamic caustic experiment and PMMA model. The evolution of dynamic intensity factor in the crack-tip field was studied in experiment. And the mechanism of crack propagation while the crack runs through the joint plane was analyzed. In addition, the crack propagating speed was obtained as well. The experimental results show that the dynamic intensity factor at the crack-tip and the propagating speed decreased dramatically while the cracks propagated through joint plane, but afterwards, the intensity factor enhances. When the crack runs through the joint plane, it would deviate a short distance along the joint, and it would continue to propagate in its initial direction. The results of the present research can provide the theoretical basis about the blasting fracture of rock mass with joints.