气体压力加卸载过程中无烟煤变形及渗透特性的试验研究  

EXPERIMENTAL STUDY OF PERMEABILITY AND DEFORMATION OF ANTHRACITE DURING PROCESS OF GASEOUS LOADING-UNLOADING

作　　者：袁梅[1,2,3,4] 许江[1,2] 李波波[1,2,3,4] 曹偈[1,2] 张敏[1,2] 陈钰婷[1,2] 

机构地区：[1]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044 [2]重庆大学复杂煤气层瓦斯抽采国家地方联合工程实验室,重庆400044 [3]贵州大学矿业学院,贵州贵阳550003 [4]贵州大学贵州省非金属矿产资源综合利用重点实验室,贵州贵阳550003

出　　处：《岩石力学与工程学报》2014年第10期2138-2146,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家科技重大专项资助项目(2011ZX05034–004);国家重点基础研究发展计划(973)项目(2011CB201203);重庆大学西南资源开发及环境灾害控制工程教育部重点实验室访问学者基金项目

摘　　要：利用自主研发的含瓦斯煤热流固耦合三轴伺服渗流装置,以无烟煤型煤试件为研究对象,进行不同轴压、围压条件下气体压力加卸载过程中渗流试验研究,模拟不同煤层深度,以探讨煤变形及瓦斯运移演化规律。研究结果表明:(1)在加载过程中,煤应变量减小,吸附瓦斯产生较大的膨胀变形,呈现线性关系,在卸载过程中,煤应变呈增大趋势,煤逐渐被压缩。随轴压、围压增大,下降单位气体压力引起的煤应变升高量降低,应变响应程度减小。(2)在加载过程中,随气体压力升高,渗透率先减小后增大趋势,煤渗透率呈类似"V"型变化趋势,气体压力在1.2 MPa左右存在明显的拐点,体现煤孔隙扩张的程度和吸附瓦斯层增厚程度影响,依赖于吸附作用或有效应力占主导地位。在卸载过程中,随着气体压力降低,煤渗透率呈先减小后增大趋势,渗透率增大且变化速度加快,主要依赖有效应力作用或基质收缩的主导地位差异。(3)随有效应力的增大,煤渗透率呈先减小后增大的趋势。煤渗透率随有效应力增大呈对数函数或指数函数关系。(4)气体压力具有典型二阶段特征,同时渗透率与体积应变具有密切关系,体现出有效应力、吸附膨胀与煤基质收缩同时对裂隙等内部结构的影响。The homemade triaxial servo-controlled seepage equipment was used to investigate the coal containing methane under the coupled action of thermo-fluid-solid. The gaseous loading-unloading tests under the different confining pressures and axial compressions were carried out to explore the process of the coal deformation and gas migration at different seam depths. During the loading process, the strain of coal decreases linearly withincreasing gas pressures, while during the unloading process, the strain of coal increased with the decreasing ot gas pressures. With the axial compression and the confining pressure increasing, the variations of the strain of coal under unit gas pressure reduce. As the gas pressure increases in the loading process, the permeability of coal decreases firstly then increases, which exhibits a V-shape. The permeability of coal has a turning point at the pressure about 1.2 MPa, which indicates that the expansion degree of coal porosity and the thickness of adsorption layer depends on the adsorption or the dominance of effective stress. As the gas pressure decreases during the unloading process, the permeability of coal decreases firstly then increases due to the effective stress or the effective stress dominance. With the effective stress increases, the permeability of coal decreases firstly then increases. The change of permeability caused by the effective stress is a logarithmic or exponential function in the different intervals. The gas pressure shows a typical of two-stage characteristics. The permeability and the volumetric strain are closely related to each other, indicating that the effective stress, the expansion due to absorption as well as the matrix shrinkage all affect the internal structures of coal.

关 键 词：采矿工程 气体压力 有效应力 渗透率 变形 

分 类 号：TD713[矿业工程—矿井通风与安全]