The 4th International Symposium on Mine Safety Science and Engineering (ISMSSE2018)

296 / 2018-05-01 22:34:09

Fracturing mechanism and parameter optimization on hydraulic blasting of coal mine sealing wall

Concrete wall; blasting demolition; hydraulic blasting; fracturing mechanism; Response surface methodology; single-factor experiment

Mine occupational health and environmental safety > Explosion-proof

To reveal the fraction mechanism of coal mine sealing wall under hydraulic blasting and conduct parameter optimization for blasting, the Mises criterion was employed to establish the formation conditions for the fracture zone and cracked zone with significant features of the sealing wall influenced by hydraulic blasting load. The reaction mechanism of stress wave and high-pressure gas expansion on cracking in sealing wall was analyzed. A novel decision method for determining the medium crushing zone, radial crack range was proposed using the maximum tensile-stress theory. Combining with the principles blasting fracture and the minimum resistance line, the charge content, the water content, the reserved hole and other parameters were determined, and the effects of charge, water and other parameters on the expansion range of fracture zone inside the wall were analyzed using the nonlinear dynamics software LS-DYNA. Besides, Design expert was used to investigate the response surface methodology by Box—Behnken based on the single factor test, the order of factors influence the crack propagation inside the wall is: water > explosive > aperture. At the same time, the optimized experimental conditions was forecast by Design expert as below: the charge 20g, water 500ml. The research methodology and conclusions provide scientific basis and technical support for the hydraulic demolition of coal mine sealing wall.