三轴加卸载下煤岩强度及变形破坏特征  

Strength and deformation failure characteristics of coal rock under triaxial loading and unloading

作　　者：蒋力帅[1] 李丕茂 王庆伟 王宗可 李春盎 黄屹峰 JIANG Lishuai;LI Pimao;WANG Qingwei;WANG Zongke;LI Chun'ang;HUANG Yifeng(College of Energy and Mining Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;Taian Xinda Information Technology Co.,Ltd.,Taian,Shandong 271099,China)

机构地区：[1]山东科技大学能源与矿业工程学院,山东省青岛市266590 [2]中国矿业大学煤炭精细勘探与智能开发全国重点实验室,江苏省徐州市221116 [3]泰安市新达信息技术有限公司,山东省泰安市271099

出　　处：《中国煤炭》2025年第1期109-121,共13页China Coal

基　　金：国家自然科学基金面上项目(52474103);山东省自然科学基金(重大基础研究项目)(ZR2024ZD22);山东省自然科学基金面上项目(ZR2024ME031)。

摘　　要：深部煤岩体处于高应力的三向应力状态在掘进与回采等工程扰动影响下,煤岩体的三向应力平衡状态被打破。为研究煤岩体的变形破坏特征与其所处应力状态之间的关系,开展了煤岩体在不同围压下的三轴压缩实验和不同加卸载路径下的三轴加卸载实验,借助应力应变曲线、煤样破坏形态素描图及裂隙面分形维数,探究了围压与不同卸载路径对其强度与变形破坏特征的影响。研究结果表明:煤岩三轴压缩强度与围压呈现非线性关系,弹性模量与围压呈现二次函数关系;在卸载条件下,其力学特性和破坏形式与加载条件下有着本质的区别;三轴加卸载下煤岩最大主应力大幅度减小,有明显的扩容现象,表现出明显的脆性破坏;经历卸载过程的煤样,与同等围压下三轴压缩相比,破坏后裂隙面分形维数普遍增大,破碎程度加剧。Deep coal and rock masses are subjected to high-stress triaxial stress conditions,and the equilibrium of these stresses is disturbed by engineering activities such as tunneling and mining.To examine the relationship between deformation and failure characteristics of coal rock and its stress state,triaxial compression tests under different confining pressures,as well as triaxial loading and unloading tests along different paths,were conducted.Stress-strain curves,failure sketches of coal samples,and fractal dimensions of fracture surfaces were used to investigate the effects of confining pressure and loading/unloading paths on the strength and deformation characteristics.The results showed that the triaxial compressive strength of coal rock exhibited a nonlinear relationship with confining pressure,while the elastic modulus followed a quadratic function relationship with confining pressure.Under unloading conditions,its mechanical properties and failure modes were fundamentally different from those under loading conditions.During triaxial loading and unloading,the maximum principal stress of coal rock decreased significantly,accompanied by marked dilation and evident brittle failure.Compared to triaxial compression under the same confining pressure,coal samples subjected to unloading process exhibited increased fractal dimensions of the fracture surfaces,indicating greater fragmentation.

关 键 词：三轴加卸载 煤岩体 应力应变 强度特征 破坏特征 

分 类 号：TD315[矿业工程—矿井建设]