The Study On Permeability Increasing Experiments And Techniques By Deep Hole Pre-splitting Blasting With Powder-emulsionin Explosive In Low Permeability Coal Seam

Gas-related dynamic disaster has been one of the most dangerous disasters in coal mine. Thedeep-hole pre-splitting detonation technique provides an efficient way to deal with this problem byimproving the permeability of low-permeability and gas-rich coal seam to enhance the gas drainage.The detonation performance of the explosive, however, decides the detonation effect, since itimposes a direct influence on the range of the crack zone and the consequent extraction rate of gas.Comparing with the emulsion explosive, the powder-emulsion explosive gives a better waterresistant property, reposition stability, charging convenience and detonation performance. In orderto obtain a comparative analysis of the detonation effect between the emulsion explosive and thepowder-emulsion explosive, a numerical simulation was conducted to simulate the crackproduction and extension induced by detonation, the attenuation of the shock wave pressure, thechange of the stress field and the damping of the energy. Since the coal seam under the realcondition bears in-situ stress, the detonation induced crack extension under the vertical in-situstress and the different lateral pressure coefficients were also examined. The relationship betweenthe crack length and the vertical in-situ stress, and the relationship between the crack length and thelateral pressure coefficient were obtained from the simulation. According to the performance of thepowder-emulsion explosive, the in-situ charging operation was proposed.