摘要
为了改进渗透率模型,定量描述层理煤岩在力学变形与渗透行为上的各向异性特征,将平行层理煤岩的裂隙开度作为基准,引入了等效裂隙开度系数,将非平行层理煤岩的裂隙开度等效,提出了一种基于等效裂隙开度系数的层理煤岩渗透率演化模型。结果表明:随着层理角度增大,层理煤岩的渗透率显著降低,且层理角度越大的煤岩,随着气体压力的变化其动态渗透率变化幅度越小;有效应力与吸附效应对于渗透率的演化有显著影响,但在不同的力学边界下,二者属于竞争关系,有效应力对于渗透率的影响在恒定围岩应力边界下处于优势地位,而吸附效应则在位移固定边界条件下占据主导地位;对于层理煤岩瓦斯抽采,顺层理方向抽采可极大的提高抽采效率。
In order to improve the anisotropy characteristics of permeability model in quantitatively describing mechanical deformation and permeability behavior of bedding coal rocks,take the fracture aperture of parallel bedding coal rocks as the benchmark,introduce the equivalent fracture aperture coefficient,and make the fracture aperture of non-parallel bedding coal rocks equivalent,we propose a permeability evolution model of bedding coal and rocks based on equivalent fracture aperture coefficient.The results show that with the increase of the bedding angle,the permeability of bedding coal and rocks decreases significantly,and the larger the bedding angle is,the smaller the dynamic permeability changes with the change of gas pressure;the adsorption effect has a significant impact on the evolution of permeability,but they are in a competitive relationship under different mechanical boundaries.The effect of effective stress on permeability is in a dominant position under the boundary of constant surrounding rock stress,while the adsorption effect is dominant under the fixed displacement boundary condition;for gas drainage of bedding coal and rock,drainage along the bedding direction can greatly improve the drainage efficiency.
作者
亓宪寅
王胜伟
耿殿栋
付鹏
QI Xianyin;WANG Shengwei;GENG Diandong;FU Peng(School of Urban Construction,Yangtze University,Jingzhou 434023,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)
出处
《煤矿安全》
CAS
北大核心
2023年第8期1-11,共11页
Safety in Coal Mines
基金
湖北省自然科学基金资助项目(2020CFB367)。
关键词
瓦斯抽采
层理煤岩
等效裂缝开度
渗透率
气固耦合
gas extraction
bedded coal and rock
equivalent fracture aperture
permeability
gas-solid coupling
