采用动态应变测试和高速摄影系统,对切缝管空气间隔装药定向断裂爆破机理进行研究。共采用4种装药结构,研究发现:当轴向不耦合系数为1.5时,炮孔两侧测点的应变比最大为2.1,压力持续作用时间达到9μs,定向断裂效果显著。通过高速摄影测试发现裂纹的扩展速度并不是一个常量,扩展速度呈现震荡变化,并对其形成机理进行分析。在模型实验的基础上,分别采用不耦合装药系数1.5和1.66,进行地下隧道和露天边坡工程爆破现场实验,取得了良好的效果。
In this work we performed experimental tests using the dynamic strain test and high speed photography system to study the mechanism of the air-deck slotted charging structure blasting, with four axial air-deck structures adopted. The results show that the highest strain ratio reached 2.1 as the axial decoupling coefficient 1.5, and the corresponding function time of pressure was 9 μs. The best result of directional fracture was achieved. The crack propagation process was recorded by high- speed photography, which show that the propagation speed of the crack was not a constant. The expansion speed of the crack fluctuated with time, and illustrated the phenomenon. Finally, the field tests were performed in the underground tunneling and open slope projects with 1.50 and 1.66 as the axial decoupling coefficient respectively, and with good results achieved.