Study on the influence of slit structure on safe and efficient directional fracture blasting effect

In order to study the influence of slit structure on the blasting effect of slit charge, the super dynamic strain test system and photographic equipment were used to study the dynamic response of slit charge blasting and the distribution of blasting cracks under different slit shapes and slit angles. The results show that changing the shape of the slit does not make the energy-gathering and damage-reducing blasting effect of the slit cartridge disappear, but it will affect its effect. Compared with the round hole slit, the peak strain in the slit direction of the strip slit cartridge blast is larger, the directional crack forming is more obvious, and the blasting effect is better. The energy accumulation and loss reduction effect of the blasting of the strip slotted cartridge increase first and then decrease with the increase of the slit angle. When the slit angle is 20°, the energy accumulation and loss reduction effect of strip slit charge blasting are the largest, the distribution of blasting cracks is the best, and the directional fracture blasting effect of slit charge is the best. Finally, based on the research results of model test, combined with the actual situation of the construction site, the slotted cartridge is applied to the pre-splitting blasting of open-pit slope. Compared with the ordinary cartridge pre-splitting blasting, the slope roughness after blasting is reduced by 46.2%, the half-hole rate of blast hole is increased by 20.5%, the blasting vibration intensity is reduced by 60.3%, and the directional fracture control blasting effect is good.