摘要
研究煤体灾变破坏时力学特征响应机制对维持煤矿开采稳定性具有重要意义。以大尺寸煤体为研究对象,开展常规三轴压缩试验,监测不同围压下煤体力学行为,发现煤体亚失稳阶段出现条件及规律,并揭示了三轴压缩下煤体破坏机制。结果表明:全应力-应变曲线5个阶段阈值随围压增大而增加,峰值应变与围压相关性较高。幂律方程对煤体灾变加速增长阶段轴向应变率拟合效果较好。试验环境接近煤体地下真实状态时,亚失稳才会出现;准静态与准动态阶段约占亚失稳总时间的37.5%、62.5%,准动态阶段应力与径向应变演化更为剧烈。残余强度的敏感性高于峰值强度,随着围压增大强度衰减系数逐渐降低。同时煤体以剪切破坏为主并伴有张拉破坏,不同位置裂缝宽度有所不同。
Studying the response mechanism of mechanical characteristics during catastrophic failure of coal is crucial for maintaining mining stability.Using large-size coal specimens as the research subject,conventional triaxial compression tests were conducted to monitor the mechanical behavior of coal under different confining pressures.The conditions and laws of the coal's sub-instability stage were identified,and the failure mechanism of coal under triaxial compression was revealed.The results indicate that the thresholds of the five stages in the complete stress-strain curve increase with rising confining pressure,with peak strain showing a high correlation with confining pressure.The power-law equation provides a good fit for the axial strain rate during the accelerating phase of coal catastrophe.The sub-instability stage only appears when the test environment closely approximates the actual underground conditions of coal.The quasi-static and quasi-dynamic phases account for approximately 37.5%and 62.5%of the total sub-instability time,respectively,with more intense evolution of stress and radial strain occurring during the quasi-dynamic phase.Residual strength is more sensitive than peak strength,and the strength attenuation coefficient gradually decreases as confining pressure increases.Coal failure is predominantly shear-based,accompanied by tensile failure,with varying crack widths at different locations.
作者
马骥
刘冬生
任建举
张文龙
寇宏刚
MA Ji;LIU Dongsheng;REN Jianju;ZHANG Wenlong;KOU Honggang(School of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;School of Energy and Mining,China University of Mining andTechnology-Beijing,Beijing 100083,China;School of Resource Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China;School of Architecture and Engineering,Qingdao Huanghai University,Qingdao 266427,China;School of Civil Engineering,Xijing University,Xi’an 710123,China;Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resources,Wuhan 430081,China)
出处
《煤炭工程》
北大核心
2025年第11期150-157,共8页
Coal Engineering
基金
国家自然科学基金青年科学基金项目(52404119)
河南省自然科学基金青年项目(242300421451)
冶金矿产资源高效利用与造块湖北省重点实验室开放基金项目(2024zy001)。
关键词
岩石力学
全应力-应变曲线
亚失稳
灾变前兆
力学特征
rock mechanics
complete stress-strain curve
sub-instability
catastrophic precursors
mechanical characteristics
