Blasting damage control of slit charge structure

This study investigates the control mechanism of blasting damage to surrounding rock and conducts a quantitative evaluation of the damage using laboratory experimentation and field test. A comprehensive evaluation system of blasting damage for roadway contour quality and internal damage of surrounding rock is established using digital image processing, multifractal spectrum calculation, CT scanning, borehole televiewer, and acoustic testing. The results show that the evolution of blasting damage conforms with fractal law, and the relationship between blasting damage area and fractal dimension follows a power function. Slit charge blasting causes the initiation and propagation of two straight main cracks along the slit. The peak velocity measured at the center of the slit charge is found to be 1.74 times that of the ordinary charge. The slit charge can effectively reduce the blasting damage.