To obtain the correlation between the macro- and microdamage of coal under the coupling action of gas adsorption and stress, the pore structure and mechanical properties of gas-bearing coal under axial loading and the correlations between these factors were studied. The results show that the pore size distribution of coal hardly changed with the change in axial stress, while 45.26% of the micropores and small pores were transformed into mesopores and macropores with the increase in adsorbed gas content within the tested range. Due to different microdeterioration mechanisms, the strength and elastic modulus of gas-bearing coal do not obey a single damage evolution criterion, and their deterioration rates with increasing adsorbed gas content were 27.96% and 11.20%, respectively, within the tested range. The trends of the variations in strength deterioration rate, fracture fractal dimension and pore volume fractal dimension of gas-bearing coal were consistent, and their correlations were greater than 99.2%, but the degrees of the changes in these factors were quite different, indicating that the damage factor at the macroscale cannot be extended to the microscale. To overcome this limitation, a multiscale damage constitutive model considering macro- and microdamage was constructed by using micro-based phenomenological damage theory. The verification indicated that the model accuracy could reach 98.97%, indicating a high reliability.

为获得瓦斯吸附与应力耦合作用下煤的宏观和微观破坏之间的相关性，研究了轴向载荷下含气煤的孔隙结构和力学性能以及这些因素之间的相关性。结果表明，煤的孔径分布几乎不随轴向应力的变化而变化，而在测试范围内，随着吸附气含量的增加，45.26%的微孔和小孔转化为中孔和大孔。由于微劣化机理不同，含气煤的强度和弹性模量不服从单一的损伤演化准则，其随吸附瓦斯含量增加的劣化率分别为27.96%和11.20%，均在测试范围内。含气煤强度劣化率、裂缝分形维数和孔隙体积分形维数变化趋势一致，相关性均大于99.2%，但这些因素变化的程度差异较大，说明：宏观尺度的损伤因子不能扩展到微观尺度。为了克服这一限制，利用基于微观的唯象损伤理论，构建了考虑宏观和微观损伤的多尺度损伤本构模型。经验证，模型准确率可达98.97%，可靠性高。但这些因素的变化程度差异较大，说明宏观尺度的破坏因素不能扩展到微观尺度。为了克服这一限制，利用基于微观的唯象损伤理论，构建了考虑宏观和微观损伤的多尺度损伤本构模型。经验证，模型准确率可达98.97%，可靠性高。但这些因素的变化程度差异较大，说明宏观尺度的破坏因素不能扩展到微观尺度。为了克服这一限制，利用基于微观的唯象损伤理论，构建了考虑宏观和微观损伤的多尺度损伤本构模型。经验证，模型准确率可达98.97%，可靠性高。