煤体渗透率演化特征的研究对于合理布置煤层瓦斯抽采参数、提高瓦斯抽采产量具有十分重要意义。为研究不同煤体应力及瓦斯压力对渗透率的影响，开展了瓦斯吸附扩散与受载煤体变形实验，建立了受载煤体分段渗透率动态演化模型，结合实验测试结果对所建立模型的合理性进行验证。研究结果表明：瓦斯吸附量及煤体变形量均随气体压力增大呈Langmuir型变化规律，煤体瓦斯动扩散系数随时间变化呈指数衰减趋势；随着瓦斯压力降低，受载煤体膨胀变形量逐渐减小，渗透率逐渐增大，受载煤体渗透率及膨胀变形量均随煤体应力增大而逐渐降低，应力加载煤体渗透率整体呈现“V”形变化规律，应力峰值处煤体渗透率最小；所建立的煤体渗透率模型中，考虑了瓦斯吸附引起的基质与裂隙变形耦合作用、基质瓦斯动态扩散作用及基质与裂隙物质交换作用；利用实验结果对所建立煤体分段渗透率模型的合理性进行验证，基于弹性变形的煤体渗透率模型能够很好反映出煤体弹性变形阶段的渗透率演化特征，实验范围内，煤体渗透率实验测试与数值模拟结果绝对误差为−0.135×10⁻¹⁵～0.296×10⁻¹⁵ m²，由于渗流引起的煤体体积应变绝对误差为−0.327×10⁻⁵～2.026×10⁻⁵；考虑塑性变形的煤体渗透率模型也可以反映出煤体应力峰后渗透率变化规律，实验测试结果与数值计算结果的绝对误差为−0.435×10⁻¹⁵～0.997×10⁻¹⁵ m²。

The study on the evolution characteristics of coal permeability is of great significance for rationally determining gas extraction parameters and increasing gas extraction efficiency. In order to study the effects of different coal stresses and gas pressures on coal permeability, the experiment on the deformation of stress-loaded coal and gas adsorption-diffusion was conducted, the segmented dynamic model of coal permeability was established, and the rationality of the established model was verified by the experimental results. The results shown that the gas adsorption amount and coal deformation both shown a Langmuir-type with the increasing gas pressure, and the dynamic diffusion coefficient of gas decreased exponentially with time. As the gas pressure decreased, the expansion deformation of the stress-loaded coal decreased, and the permeability increased gradually. The permeability and expansion deformation of stress-loaded coal gradually decreased with the increasing stress. The coal permeability shown a “V” shape with continuous stress loading, and it reached the smallest at the stress peak. The coupling between matrix and fracture deformation caused by gas adsorption, the dynamic diffusion of gas in matrix, and the mass exchange between matrix and fracture were all considered in the established permeability model of coal. The rationality of established segmented model of coal permeability was verified by the experimental results. The permeability model of coal based on elastic deformation can reflect the permeability evolution at the stage of elastic deformation. Within the experimental range, the absolute error between the experimental test and numerical simulation results of coal permeability was −0.135×10⁻¹⁵～0.296×10⁻¹⁵ m², and the absolute error of volumetric strain of the coal due to gas seepage was −0.327×10⁻⁵～2.026×10⁻⁵. The permeability model considering plastic deformation can also reflect the permeability after stress peak. The error between experimental and numerical results was −0.435×10⁻¹⁵～0.997×10⁻¹⁵ m².