不同围压下煤岩力学三轴试验研究  

Triaxial Test Study of Coal Rock Mechanics under Different Surrounding Pressure

作　　者：陶恩生 TAO Ensheng(National Energy Group Ningxia Coal Industry Co.,Ltd.Shuangma No.1 Mine,Lingwu 750408,China)

机构地区：[1]国家能源集团宁夏煤业有限责任公司双马一矿,宁夏灵武750408

出　　处：《煤矿现代化》2024年第5期14-19,共6页Coal Mine Modernization

摘　　要：目的为探究不同围压下煤的力学特性、强度特性和破坏机制,以王庄煤矿3号煤层原煤为研究对象,采用非接触式数字图像处理技术开展不同围压下煤岩的常规三轴加载实验,探究赋存深度对煤岩弹性模量、残余应力和应力集中现象的规律,研究结果表明:试件在5 MPa围压下的轴向、径向以及体向的峰值应变为1.5%、0.4%和0.8%,峰值应力接近于50MPa;实验改用7MPa围压后,试件的轴向、径向以及体向的峰值应变相较于前者增幅分别为25%、20%和29%,峰值应力增幅17%;围压为9MPa时,试件的轴向、径向以及体向的峰值应变相较于7MPa增幅分别为29%、29%和13%,峰值应力较7MPa增幅25%;随着围压的增大,试件的弹性模量呈现二次线性增长趋势,随围压的增加煤岩的残余应力呈非线性型增长趋势;围压超过某一临界值时,围压对煤体破坏时间有显著影响,不同围压下煤岩达到峰值强度所用加载时间不同;煤岩峰值强度随围压增加呈线性增长趋势,强度参数C、φ值分别为2.9MPa,50°;煤岩在三轴载荷过程中会出现应力集中现象,围压为5MPa时应力集中较明显处有3处,围压为7MPa时应力集中较明显处有4处,围压为9MPa时应力集中较明显处有6处,围压越大,应力集中现象越明显。研究结果为由浅至深煤岩体开采时加载破坏的强度特性和破坏机制提供参考依据。In order to explore the mechanical properties,strength characteristics,and failure mechanism of coal under different confining pressures,the raw coal of the No.3 coal seam in Wangzhuang Coal Mine was taken as the research object.Non contact digital image processing technology was used to carry out conventional triaxial loading experiments on coal and rock under different confining pressures.The law of occurrence depth on the elastic modulus,residual stress,and stress concentration phenomenon of coal and rock was explored.The research results showed that the axial direction of the specimen under a confining pressure of 5 MPa was The peak strains in radial and volumetric directions are 1.5%,0.4%,and 0.8%,and the peak stress is close to 50 MPa;After switching to a 7 MPa confining pressure in the experiment,the peak strain in the axial,radial,and volumetric directions of the specimen increased by 25%,20%,and 29%respectively,and the peak stress increased by 17%compared to the former;When the confining pressure is 9 MPa,the peak strain in the axial,radial,and volumetric directions of the specimen increases by 29%,29%,and 13%respectively compared to 7 MPa,and the peak stress increases by 25%compared to 7 MPa;With the increase of confining pressure,the elastic modulus of the specimen shows a quadratic linear growth trend,and the residual stress of coal rock shows a non-linear growth trend with the increase of confining pressure;When the confining pressure exceeds a certain critical value,it has a significant impact on the failure time of the coal body.The loading time required for the coal rock to reach its peak strength under different confining pressures is different;The peak strength of coal rock shows a linear growth trend with the increase of confining pressure,and the strength parameter C isφThe values are 2.9 MPa and 50°respectively;During the triaxial loading process,coal and rock will experience stress concentration.When the confining pressure is 5 MPa,there are 3 places where stress concentration is more pron

关 键 词：三轴加载 围压 弹性模量 应力集中 

分 类 号：TD325[矿业工程—矿井建设]