Study On Permeability Improvement And Release Of Pressure Technology Of Deep Hole Pre-splitting Blasting In11-3Coal Uncovering Of Guqiao South Coal Mine

For the problems of poor permeability of coal seam and the difficulty of the gas drainage in the Gu South Mine C13-1coal seam,the paper put forword the study of deep hole pre splitting blasting technology. By theoretical analysis, numerical simulation and similar simulation test, the paper determin suitable borehole layout for the working place and blasting parameters of the optimal solution. According to the date we measured in Huainan Mining Guqiao expose coal seams C13-1,the application of pressure relief and permeability increasing technology in low permeability and high gas coal seam in the deep hole pre-splitting blasting is studied systematically.Firstly,the paper theoretically analyses the deep hole pre-splitting blasting on the basis of summarizing the research status at home and abroad. And explosion shock wave and stress wave control hole, blasting raw gas and gas pressure were analyzed respectively at different stages in the process of crack propagation. The conclusion shows that the shock wave is the main reason of the formation of crushing zone. The effect of stress wave time and large scope, is the main area of coal and rock destruction. Stress wave in the reflection on control hole formation of tensile wave can increase the fracture zone. Detonation gas in coal and the pressure generated at the crack tip stress concentration can further promote the propagation of crack. It is concluded that crushing zone and fracture zone theoretical calculation formula of the radius.Secondly,the paper designs similar simulation test program based on similarity theory, fracture mechanics and geological data of Gu south mine ectAnd determine the simulation of coal or rock materials and ratio. The test results show:the waveform of stress wave consist of compression and tensile phase, and compression and tensile phase wave decreases with the increase of propagation distance. Deep hole pre-splitting blasting loose the effective radius is greater than3m.Finally, different hole spacing numerical model is established combined with Site conditions of Guqiao Mine C13-1coal seam of Huainan mining.The numerical model is embedded in LS-DYNA software to calculate. Numerical simulation results show:control hole provides auxiliary free surface, it can further promote the crack propagation of coal body. When the spacing of holes is3-4m, fissures communicated with each other can be formed, greatly increasing permeability of the coal and gas drainage effect.The paper determines effectively loosening radius of deep hole pre splitting blasting is3～4.5m, based on the date we measured in Huainan Mining Guqiao expose coal seams C13-1.That is consistent with the result of theoretical analysis, Similar simulation test and Numerical simulation. Gas extraction concentration can increased by0.267～1.08times within the effective radius of loose The gas extraction from scalar increased by0.25～1.23times The deep hole pre splitting blasting privodes a reliable method for gas draingage gas low permeability coal seam.