含水煤岩裂隙压缩特征及渗透特性研究  

Study on fracture compression and permeability of water-bearing coal

作　　者：李波波[1,2,3] 成巧耘 李建华 王斌[1] 许江[4] 高政 LI Bobo;CHENG Qiaoyun;LI Jianhua;WANG Bin;XU Jiang;GAO Zheng(College of Mining,Guizhou University,Guiyang,Guizhou 550025,China;National Local Joint Engineering Laboratory for Efficient Utilization of Dominant Mineral Resources in Karst Mountain Area,Guizhou University,Guiyang,Guizhou 550025,China;Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources,Guizhou University,Guiyang,Guizhou 550025,China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,China)

机构地区：[1]贵州大学矿业学院,贵州贵阳550025 [2]贵州大学喀斯特山区优势矿产资源高效利用国家地方联合工程实验室,贵州贵阳550025 [3]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550025 [4]重庆大学煤矿灾害动力学与控制国家重点实验室,重庆400044

出　　处：《岩石力学与工程学报》2020年第10期2069-2078,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51804085,51911530203);贵州省科技计划资助项目(黔科合平台人才[2018]5781号)。

摘　　要：为研究深部煤岩开采过程中含水率、有效应力与裂隙压缩性对煤岩渗透率的影响规律,利用HCA型高压容量法吸附装置和含瓦斯煤热-流-固三轴伺服渗流装置分别进行不同含水率条件下煤岩的等温吸附试验和渗流试验。在此基础上建立考虑含水率与裂隙压缩性综合作用的煤岩渗透率模型,并分析煤岩在不同含水率条件下,煤岩有效压缩性系数与渗透率的响应机制。结果表明:(1)气体压力恒定为1.0MPa时,煤岩轴向应变与径向应变随有效应力的增大而增大;而在有效应力不变,煤岩含水率变化的过程中,其轴向应变与径向应变随含水率增大逐渐减小,瓦斯流量也随含水率的增大而减小。(2)随着气体压力的增大,煤岩瓦斯吸附量先增大后趋于平缓,在气体压力持续增大的过程中,吸附量逐渐趋于饱和,等温吸附曲线的变化逐渐趋于平缓。(3)在同一含水率条件下,煤岩渗透率随有效应力的增大而减小。当有效应力恒定时,水分对煤岩的渗透率的大小具有抑制作用,即含水率增大过程中渗透率呈减小趋势。不同含水率下煤岩的吸附变形量与有效压缩性系数之间呈负相关,且有效压缩性系数随含水率的增大而减小。(4)建立了考虑含水率和裂隙有效压缩性综合作用的煤岩渗透率模型,其中渗透模型计算值的与实测值基本吻合,可较好地表征不同含水率条件下煤岩渗透率随有效应力升高的变化规律。In order to study the influence of the water content,the effective stress and the fracture compressibility on the permeability of coal during deep coal mining,isothermal adsorption test and seepage test of coal under different water content conditions were respectively performed by using HCA-type high-pressure capacity method adsorption device and gas-containing coal thermal-fluid-solid triaxial servo seepage device.A coal permeability model considering the combined effect of the water content and the fracture compressibility was established,and the change law of the effective compressibility coefficient and the permeability of coal under different water content conditions was analyzed.The results show that,when the gas pressure is constant at 1 MPa,the axial and radial strains of coal increase with increasing the effective stress,and that,when the effective stress is constant,the axial and radial strains of coal and the gas flow decrease gradually with increasing the water content.As the gas pressure increases,the coal gas adsorption capacity first increases and then tends to be saturated after the gas pressure reaching a certain value between 1 and 2 MPa.Under the same water content,the permeability of coal decreases with increasing the effective stress.When the effective stress is constant,water has a limiting effect on the permeability of coal,in other words,the permeability decreases with increasing the water content.There is a negative correlation between the adsorption deformation and the effective compressibility coefficient at different water cuts,and the effective compressibility coefficient has a negative correlation with the water cut.The calculated permeability by the developed model is basically consistent with the measured,showing that the developed model can better characterize the evolution law of the coal permeability with increasing the effective stress under different water content conditions.

关 键 词：岩石力学 煤岩 等温吸附 渗透率 含水率 有效压缩性系数 

分 类 号：TU45[建筑科学—岩土工程]