为量化分析含水饱和度对混凝土和砂岩气体渗透性的影响规律，揭示其内在机制，并为压缩空气储能地下硐库密封性评估提供依据，开展不同含水状态下多孔介质高压气体渗流试验。采用真空饱和法与失水法精确控制C45混凝土、C50混凝土和中砂岩试样的含水饱和度（0%、25%、50%、75%、100%），利用高压气体渗透测试平台在0.5～8.5 MPa气压范围内开展测试，获得不同含水饱和度下的气体渗透率数据；引入修正Kozeny经验模型进行拟合，并与低气压条件下的已有研究成果进行对比。结果表明： １）气体渗透率随含水饱和度升高呈３阶段非线性衰减，饱和度低于25%时衰减缓慢，饱和度在25%～75%时衰减加快，饱和度超过75%时突变式下降，临界饱和度阈值为75%。２）内在机制在于液相赋存状态发生结构性转变，低饱和度时水相以孤立环状分布于小孔隙，气相通道保持连通；随饱和度升高，水相逐渐填充并堵塞主要渗流孔隙，气相有效连通路径减少；饱和度超过75%时水相形成连续分布，气相连通网络被大面积阻断，导致渗透率急剧下降。３）修正Kozeny模型与试验数据拟合良好，能够描述含水多孔介质气体渗透行为。
In this study, experiments were conducted on the high-pressure gas permeability characteristics of porous media under different water saturation states to quantitatively analyze the influence of water saturation on the gas permeability of concrete and sandstone, reveal its underlying mechanism, and provide a basis for assessing the sealing performance of compressed air energy storage underground caverns. The vacuum saturation method combined with the water loss method was employed to precisely control the water saturation of C45 concrete, C50 concrete, and medium-grained sandstone specimens at five target levels: 0%, 25%, 50%, 75%, and 100%. The test was carried out in the range of 0.5－8.5 MPa using the highpressure gas permeation test platform, and gas permeability data were obtained under different saturation degrees. A modified Kozeny empirical model was introduced to fit the experimental results, and a comparative analysis was conducted with existing studies on cement-based materials under low gas pressure conditions. The results indicate that the gas permeability exhibits a three-stage nonlinear decay with increasing water saturation: the decay is slow when the saturation is below 25%, accelerates in the 25%－75% interval, and shows a sharp drop after exceeding 75%, the critical saturation threshold. The intrinsic mechanism behind this phenomenon lies in the structural transformation of the liquid-phase occurrence state: at low saturation, the water phase is distributed in isolated rings or films within small pores, while the gas channels remain connected. As saturation increases, the liquid phase gradually fills and blocks the main seepage pores, reducing the effective connected pathways for the gas phase. When the saturation exceeds 75%, the water phase forms a continuous distribution, leading to extensive blockage of the gas-phase connected network and a sharp decline in permeability. The modified Kozeny model fits the experimental data well and can describe the gas permeability behavior of water-bearing porous media.
