利用工业CT扫描系统，观测不同气体压力条件下煤体内部微裂隙萌生扩展特点，为揭示煤层瓦斯流动产出控制因素提供新的依据。结果表明：非吸附性气体作用下，随孔隙压力的升高，煤体内部微裂隙的萌生和扩展愈加明显，裂隙体积和裂隙面积百分占比增长率随之逐渐减小，符合气体压力影下的裂隙扩展方程，微裂隙扩展主要受控于应力集中效应和煤基质收缩效应。吸附性气体作用下，随吸附时间的延长，煤体内部微裂隙的萌生和扩展则越来越显著，直至扩展平衡；裂隙体积和裂隙面积百分占比增长率随之逐渐变小，符合吸附时间影响下的裂隙扩展方程；裂隙扩展主要受应力集中效应、煤基质收缩效应、蚀损作用和劣化机制影响；吸附压力越大，煤体所需的吸附平衡时间愈长；微裂隙扩展平衡时间长于气体吸附平衡时间，裂隙扩展具有明显的滞后性。

Using an industrial CT scanning system, we observed the characteristics of micro-fracture Generation and expansion in coal under different gas pressure conditions, providing a new basis for revealing the factors controlling the gas flow output of coal seams. The results of the test analysis showed that: under the action of non-adsorbed gas, the growth rate of fracture volume and fracture area percentage decreases gradually as the pore pressure increases and the sprouting and expansion of microfractures inside coal becomes more obvious. Fracture expansion equation under the influence of pore pressure is satisfied; microfracture extension is mainly controlled by stress concentration effect and coal matrix shrinkage effect. Under the action of adsorptive gas, with the extension of adsorption time, generation and expansion in coal of micro fissures become more and more significant until the expansion equilibrium; the growth rate of fissure volume and fissure area percentage then gradually becomes smaller, in line with the fissure expansion equation under the influence of adsorption time; the fracture extension is mainly affected by stress concentration effect, coal matrix shrinkage effect, erosion effect and deterioration mechanism. The larger the adsorption pressure the longer the adsorption equilibrium time required for the coal; the micro fissure expansion equilibrium time is longer than the gas adsorption equilibrium time, and the fissure expansion has obvious hysteresis.