Abstract:In order to study the pore structure and fractal characteristics of coal under the influence of tectonic action, this paper uses low temperature nitrogen adsorption method, mercury intrusion experiment and other methods, and combines fractal theory to quantitatively analyze the pore distribution of coal samples inside and outside the outburst holes in Sanjia Coal Mine. Through the combined analysis of MIP and N2GA, the critical pore sizes of soft and hard coal are 59 nm and 86 nm, respectively. The pore volume of hard coal is mainly distributed in pores below 100 nm, and there is little difference in pore volume distribution of tectonic coal. The pore volume of medium and large pores is significantly higher than that of hard coal. The specific surface area of tectonic coal is more than 4 times larger than that of hard coal, and the pore volume is 24.5 % more. According to the analysis of fractal theory, the fractal dimensions of seepage holes and adsorption holes of tectonic coal are 3.03 and 3.77 respectively, which are higher than those of primary coal 3.01 and 3.72. The thermodynamic fractal dimension of tectonic coal is as high as 2.916, and tectonic coal has more complex pore structure and rougher pore surface.