The distribution characteristics of blasting fractures and their engineering applications under the coupling effect of in-situ stress and energy-releasing end structure
LI Jie
Abstract：As an effective technical means to improve the permeability of coal seam,pre-splitting blasting has important application value in the field of coal mine gas drainage.In order to accurately explore the distribution characteristics of blasting cracks under the coupling effect of in-situ stress and energy release end structure,and optimize the construction parameters of pre-splitting blasting coal seam permeability improvement technology,similar materials were used to make briquette instead of raw coal to carry out blast-ing experiments under true triaxial conditions,and CT scanning technology was used to carry out non-destructive testing and accur-ate imaging of blasting cracks inside briquette specimens.The experimental results show that the distribution characteristics of blast-ing cracks in briquette are closely related to the structure of energy release end,and the distribution form and number of energy re-lease holes at the energy release end significantly affect the spatial distribution of blasting cracks.The energy release end of the single-hole structure is conducive to the formation of directional long cracks,and the energy release end of the porous structure is conducive to form a complex fracture network.In-situ stress has a regulating effect on the formation and expansion of blasting cracks.The greater the difference between the maximum horizontal principal stress σ1 and the minimum horizontal principal stress σ3,the stronger the expansion capacity of blasting cracks.The influence of vertical principal stress σ2 on blasting crack length is less than that of σ1 and σ3.Under the coupling effect of in-situ stress and energy release end structure,the former affects the crack propagation direction by changing the mechanical response characteristics of coal and rock mass;the latter acts on the distribution and morpholo-gical evolution of blasting cracks by accurately regulating the release of blasting energy.In addition,after the implementation of pre-splitting blasting coal seam permeability improvement measures in the coal seam of 5136 working face of Liujialiang Coal Mine,the gas drainage efficiency of the drainage hole is increased by at least 2 times,which fully proves the effectiveness of the pre-splitting blasting coal seam anti-reflection technology.
Keywords：pre-splitting blastingin-situ stressenergy release endblasting crackscoal seam permeability enhancement
Publication Date：2025-08-20
Online Publishing Date：2025-08-18(First online date of this platform, not the publication date of the document)
Pages：8( 125-132 )