Numerical Simulation Of Pre-splitting Blasting Crack Propagation Law In Low Permeability Coal Seams

Coal seam gas in the coal formation process generates and occurrence in coal and coalbearing strata of a natural gas. It exists to coal mine safety production and formed great harm, inour country and even the world has caused many mine gas explosion accidents. Gas drainage isone of the effective methods to prevent the gas disaster, with high gas in low permeability coalseam; the permeability coefficient is very low, resulting in gas drainage difficulty. Coalpre-splitting blasting technology in coal mine gas drainage and caving mining in the wideapplication of. Blasting explosion shock wave and blasting gas energy generated by explosivemoments, combined with the coal seam gas pressure driving force, so that the coal body aroundthe hole cracks, loosening and deformation, and the primary fissure expansion. Reduce the coalbed stress, greatly improve the permeability of coal seam, so as to improve gas drainage effect.Coal in the crack extension directly determines the gas occurrence, movement and drainageeffect, so the coal containing gas crack extension mechanism of pre-splitting blasting is thetheoretical basis of coal seam.In this paper, with high gas in low permeability coal seam physical and mechanicalproperties as the basis. Analysis of gas in the coal in the desorption, diffusion and seepageprocess. Combined with the characteristics of pre splitting blasting.Study of coal under explosivestress waves and detonation gas quasi static effect of the damage and fracture mechanism of.Thorough analysis of explosion gas effects on crack propagation, think blasting, crackpropagation, the broken coal seam was mainly due to the effects of the detonation gas, explosivestress wave, detonation gas and coal seam gas pressure in coal seam in pre-splitting blasting isthe main reason of crack expansion. On this basis, using the software of coal pre-splittingblasting gap expansion process numerical simulation.Using the AUTODYN program in the userdefined material model function, through theoretical analysis, the influence of coal fissureextends the main parameters of. By changing the material of the main parameters,implementation of pre splitting blasting on the entire process numerical simulation. This papercarried out a total of two groups of simulating calculation, compared with single hole under theconditions of four different time simulation results under two conditions, as well as hole spacing2m,4m two hole pattern simulation results between the two groups, respectively analyzed thestress, strain and time change trend. Results the reasonable computation time and reasonable arrangement of holes on crack propagation and coalescence plays an important role. Coalpre-splitting blasting is the object of coal containing gas, the technology for high gas and lowpermeability coal seam permeability increasing, and solution of high gas and low permeabilitycoal seam gas drainage problem provides a new effective way.