Investigating the mechanism of rock fracturing induced by high-pressure gas blasting with a hybrid continuum-discontinuum method

To study the rock-breaking mechanism resulting from high-pressure gas blasting, a hybrid continuumdiscontinuum method considering the actual breakage of rocks was presented in this study. The mechanical parameters were calibrated against the uniaxial compression test and Brazilian disc test, and the capabilities of simulating blast-induced fractures were verified by laboratory tests. After that, the differences in rock-breaking mechanism between explosive blasting and high-pressure gas blasting were compared from the perspectives of peak pressure and loading rate. The results indicated that the crack patterns, fracture mode and vibration attenuation induced by high-pressure gas blasting were significantly different from that of explosive blasting: (a) no crushing zone and fewer radial cracks were formed in high-pressure gas blasting and the spalling cracks were absent near the free face in high-pressure gas blasting; (b) the difference of rock fracture mode in high-pressure gas blasting and explosive blasting indicated that the tensile fracturing was the dominant fracture mode in high pressure gas blasting which is different from the catastrophic fragments due to compressive-sheared fracturing surrounding the borehole in explosive blasting; (c) the intensity and attenuation factors of peak particle velocity both increased with the increase of peak pressure or loading rate, which indicated that the peak particle velocity induced by explosive blasting results in more intense and faster attenuated vibration disasters than that of highpressure gas blasting.

Automated summary

This study presented a hybrid continuum-discontinuum method to investigate the rock-breaking mechanism resulting from high-pressure gas blasting, and found significant differences in crack patterns, fracture mode, and vibration attenuation between high-pressure gas blasting and explosive blasting.