Analysis on effect of primary fractures structure on physical and mechanical properties of coal rock

In order to quantitatively analyze the influence of coal rock’s primary fracture structure on its physical and mechanical properties, the coal samples with different outburst proneness were taken as the research object, using industrial CT scanning and 3D reconstruction technology, the three-dimensional characteristics of coal rock’s primary fracture structure were quantitatively described by length factor, width factor, area factor, volume factor, inclination factor and fractal factor. According to the principle of sample correlation analysis and partial least squares regression analysis, the relationship between the geometric characteristics of primary fracture structure and physical and mechanical properties was analyzed. It is found that the characteristics of primary fractures are different in coal rock media with different physical and mechanical properties, and their development degree is inversely proportional to the outburst proneness; In addition to Poisson's ratio, the physical and mechanical properties of coal and rock have a significant correlation with the geometric factors of the original fracture structure characteristics; The ability of different geometric factors to affect the physical and mechanical properties and the degree of influence of each physical and mechanical property by the geometric factors are different.