作　　者： (张东明）; (郑彬彬）; (尹光志）; (张先萌）; (杨玉顺）;

机构地区： 重庆大学煤矿灾害动力学与控制国家重点实验室

出　　处： 《煤炭学报》 2017年第S1期128-137,共10页

摘　　要： 针对煤矿开采过程中垂直应力集中及水平应力卸载所引起的岩体变形破坏和渗透特性等问题,运用自主研制的含瓦斯煤热流固耦合三轴伺服渗流试验装置,以急倾斜煤层顶板砂岩为研究对象,开展不同静水压力条件下,砂岩定轴压卸围压瓦斯三轴渗流试验,研究应力集中状态对砂岩卸围压破坏过程中变形规律及渗流特性的影响。得出的主要结论有:岩样屈服阶段存在一点,为岩样卸荷由张拉破坏向压剪破坏的转折点,且卸荷点越接近屈服强度,岩样卸荷破坏越突然和剧烈,岩体破碎度越高;初始围压(轴压)相同时,砂岩的峰值强度随初始轴压(围压)增大而有所提高;砂岩卸荷破坏卸荷量百分比随轴压增大而减小,随初始围压增大而增大;砂岩卸荷破坏后,峰值瓦斯流量与体积应变之间存在指数函数关系;砂岩卸荷破坏形态主要表现为沿层理方向的张剪混合裂缝,且微裂缝十分发育,岩样的渗透性与裂缝的发育程度具有较好的相关性。岩体渗透性与其所处的应力状态密切相关,开展采动应力下煤系砂岩的变形破坏规律及瓦斯流动特征研究对指导急倾斜煤层开采中瓦斯抽采钻孔的合理布设、提高瓦斯抽采效率具有重要的理论及现实意义。 In order to study the problem of surrounding rock deformation and permeability characteristics caused by the change of vertical stress and horizontal stress during coal mining,a self-developed device Gas Containing Coal Fluidsolid-heat Coupling Triaxial Servo Permeability Experimental Device was used. Taking the sandstone sample from the roof of steep mine as study object,different initial stresses with a certain axial stress to the influence of deformation law and permeability characteristics of the failure stress during surrounding stress unloading was studied. The main results are: there exists a point during yield stage,which is the turning point of tension failure to compression and shear failure,the closer unloading point to yield strength,the stronger degree failure of sample; with the same surrounding stress(axial stress),the peak value of sandstone rock increases with initial axial stress(surrounding stress); the unloading amount percentage of sandstone rock failure decreases with the increase of axial stress; after sandstone rock unloading failure,peak gas flow has an exponential relation with volumetric strain; the main sandstone failure form appears astension-shear mixture fissures along bedding,and the fissures are well developed,indicating there is a good relation with permeability characteristics and fissure develop degree.As far as concern,the permeability characteristics of rock are closely related to stress state it exists.Therefore,the research on deformation failure law and gas flow characteristic disturbance stress is very important to guide the layout of exploitation drill in steep coal mine and improve gas drainage efficiency.

关 键 词： 采动应力 急倾斜 砂岩 卸围压 瓦斯渗流