为探究瓦斯水合固化及加卸载条件下含瓦斯水合物煤体应变及渗透率变化规律，采用自主设计的应力–渗流–化学耦合作用煤体三轴试验装置，测量瓦斯水合物生成前后煤体渗透率及升轴压卸围压条件下煤体(3种粒径：0.425～0.850(20～40目)、0.250～0.425(40～60目)、0.180～0.250 mm(60～80目)；3种饱和度：40%、60%、80%)应变及渗透率，获取加卸载条件下应力–应变曲线确定煤体变形特征，分析瓦斯水合物生成、水合物饱和度及偏应力对煤体渗透率的影响规律，通过渗透率损失率、变形角公式对煤体渗透率影响程度、体积膨胀效应进行量化表征，基于渗透率模型初步探讨水合物分布模式对煤体渗透率的影响机制。研究表明：① 饱和度对煤体渗透率变化规律影响较为复杂，总体而言，随着饱和度增加，渗透率降低百分比越大，堵塞程度越显著。瓦斯水合物生成后，煤体渗透率明显降低，降低幅度为58.3%～83.3%(20～40目)、61.5%～95.0%(40～60目)、81.8%～90.9%(60～80目)，随着饱和度增加，煤体渗透率整体呈降低趋势，下降幅度为55.6%～86.1%。② 煤体轴向应变随着时间增加呈现出稳定增大、缓慢增大和快速增大3个阶段，煤体渗透率与应变具有一定相关性，并随着偏应力增加呈二项式函数增大、先减小后增大、先增大后减小3种趋势，二项式函数可较好预测采掘应力扰动下瓦斯水合固化后煤体渗透率变化规律。③ 引入渗透率损失率，在相同水合物饱和度下，随着偏应力增加，煤体渗透率损失率整体呈增大趋势。④ 引入体积膨胀变形角，在相同偏应力差下，随着饱和度增加，煤体体积膨胀变形角由19.0°～63.9°降至0.2°～38.2°，说明水合物饱和度越低，煤体体积膨胀效应越显著。

In order to explore the effect of hydrate formation and loading-unloading condition on the strain and permeability of gas hydrate bearing coal, the authors first measured the permeability of coal before and after gas hydrate formation, by using the triaxial testing machine for coupling action of stress, seepage, and chemical effect, as well as measured the strain and permeability of coal (three particle sizes: 0.425−0.850 mm (20−40 mesh), 0.250−0.425 mm (40−60 mesh), 0.180−0.250 mm (60−80 mesh) and three saturations: 40%, 60%, 80%) under the axial loading and confining unloading conditions. Then, the stress-strain curve was used to determine the deformation characteristic of coal during under loading and unloading conditions, the effect of hydrate formation, hydrate saturation and deviator stress on the coal permeability, the extend of coal permeability and volume expansion effect were quantitatively characterized by permeability loss rate formula and deformation angle formula. Furthermore, the influence mechanism of hydrate distribution mode was preliminarily discussed on the coal permeability with the theoretical permeability models. The results show that ① the influence of saturation on the variation law of coal permeability is more complicated. In general, with the increase of hydrate saturation, the greater the percentage of permeability reduction, the more significant the degree of blockage. The coal permeability obviously reduces after the formation of gas hydrate, with the range of reductions being 58.3%−83.3% (20−40 mesh), 61.5%−95.0% (40−60 mesh) and 81.8%−90.9% (60−80 mesh). The coal permeability decreases with the increase of hydrate saturation with a reduction between 55.6% and 86.1%. ② The axial strains of the coal exhibit three-stage process, including stability increasing, slowly increasing, and rapidly increasing with the increase of time. There is a certain correlation between the permeability and the strain of coal, and the permeability varies with the increase of deviator stress, in terms of quadratically increasing, decreasing and first increasing and then decreasing, the quadratic function can better predict the permeability variation law of gas hydrate bearing coal under mining stress disturbance. ③ Introducing the permeability loss rate, the permeability loss rate increases with the increase of the deviator stress applied on the coal under the condition of the same hydrate saturation. ④ Introducing the expansion deformation angle, the coal expansion deformation angle decreases from 19.0°−63.9° to 0.2°−38.2° with the increase of hydrate saturation under the condition of the same deviator stress, which indicates that the lower the hydrate saturation, the more significant effect of the coal expansion.