Application study on deep borehole pre-cracking blasting for permeability improvement to uncover seam in mine shaft

摘要

In order to increase the coal seam permeability and the rate of gas extraction, then eliminate the outburst danger, this article by the method of theoretical study and numerical simulation, to study the deep borehole pre-cracking blasting applied in the low permeability and high gas coal seam, then the test pointed out the coal and rock mechanics properties and the guiding role of control hole.By means of numerical simulation of stress nephogram and fracture Fig.for two blasting holes and control hole, recreating the propagation and attenuation law of stress wave in the rock, and the expansion process of the coal cracks.Finally, the test of deep borehole pre-cracking blasting was done in 13-1 seam in Xieqiao coal mine, and the test effect was ideal.The technology significantly increases the permeability of coal and improves the extraction concentration and volume, which is a positive and feasible scheme to prevent the outburst of low permeability and high gas coal seam.