高温作用后坚硬煤样单轴压缩过程中的变形强度与声发射特征  

Deformation intensity and acoustic emission characteristics of hard coal sample under uniaxial compression after high temperature

作　　者：苏承东[1,2] 宋常胜 苏发强[1,2,3] SU Chengdong;SONG Changsheng;SU Faqiang(School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo 454003,China;Collaborative Innovation Center of Coal Work Safety,Henan Province,Jiaozuo 454003,China;Shanxi Lu’an Mining(Group)Co.,Ltd.,Changzhi 046204,China)

机构地区：[1]河南理工大学能源科学与工程学院,河南焦作454003 [2]煤炭安全生产河南省协同创新中心,河南焦作454003 [3]山西潞安矿业(集团)有限责任公司,山西长治046204

出　　处：《煤炭学报》2020年第2期613-625,共13页Journal of China Coal Society

基　　金：国家自然科学基金资助项目(U1504529);河南省教育厅自然科学研究计划资助项目(2010A44002);河南省科技厅科技攻关资助项目(182102310020)

摘　　要：为了探讨高温作用对煤样力学性质与声发射特征的影响机制。利用煤样经历100,200,300,400和500℃高温自然冷却后,在单轴压缩过程中同步声发射信息检测,而后将碎煤块在JSM-6390 LV电镜进行了微观结构扫描。分析了经历不同高温自然冷却后煤样微观结构和单轴压缩过程中的变形、强度与声发射特征。研究结果表明:①高温后煤样在单轴压缩过程中可分为压密、弹性、屈服和破坏4个阶段,经历温度越高压密和屈服阶段越明显,峰值后应力跌落速度有所减缓;②高温后坚硬煤样的弹性模量、变形模量和抗压强度随温度升高呈阶段性降低,在100和500℃高温对煤样弹性模量、变形模量和抗压强度的影响显著。在100~400℃高温,高温对煤样弹性模量、变形模量的影响作用相差不大。与常态25℃煤样比较,经历100,200,300,400和500℃高温后,煤样弹性模量平均降幅依次为19.7%,19.8%,24.2%,34.3%和77.4%,抗压强度平均降幅依次为47.88%,49.99%,56.24%,56.91%和87.57%;③高温后坚硬煤样在单轴压缩变形破坏过程中始终伴随有声发射信息,在煤样加载过程中的声发射幅值、计数、能量和应力-时间曲线具有较好地对应关系,不同高温后煤样的声发射特征存在差异,声发射的幅值、计数和能量最大值并非同时发生,声发射累计幅值与时间曲线转折点早于累计计数和能量曲线转折点,且随着温度增加累计幅值与时间曲线转折点提前,而累计计数和能量曲线转折点推迟现象;④高温后煤样声发射参数与温度的关系具有分段特征,其累计幅值和计数随温度升高先增加后降低,累计能量随温度变化具有波动性;⑤高温后煤样的抗压强度与声发射累计幅值、计数和能量没有确定关系,抗压强度和声发射参数是煤样破坏不同属性反映。经历100~500℃高温作用后煤样结构发生了变化,煤样内部裂隙数目和尺度随温度增加而�In order to explore the mechanism of high temperature effect on the mechanical properties and acoustic emission characteristics of coal samples,after natural cooling at 100,200,300,400 and 500 degrees Celsius,the AE information of coal samples was detected synchronously during uniaxial compression,and then the fragments were scanned by JSM-6 390 LV electron microscopy.With the natural cooling after different temperatures heating,the micro-structure of coal samples and the deformation,strength and acoustic emission characteristics of coal samples during uniaxial compression were analyzed.The results show that ① the deformation of coal sample after the high temperature can be divided into four stages,i.e.compaction,elasticity,yield and damage in the process of uniaxial compression.The higher the temperatures experienced,the more obvious the compaction and yield stages.After peak,the stress drop is slowed;② After high temperature heating,the elastic modulus,deformation modulus and compressive strength of hard coal samples decrease with temperature increases periodically.The 100 ℃ and 500 ℃ high temperatures have a significant influence on elastic modulus,deformation modulus and compressive strength.In 100-400 ℃ temperature range,the temperatures have the same influence of elastic modulus,deformation modulus and compressive strength of the coal samples.Compared with the coal samples at a normal 25 ℃,the average decreases of elastic modulus of coal samples after 100,200,300,400 and 500 ℃ heating were 19.7%,19.8%,24.2%,34.3% and 77.4% respectively,and the average decreases of compressive strength were 47.88%,49.99%,56.24%,56.91% and 87.57% respectively;③ The deformation and failure process under uniaxial compression are always accompanied by acoustic emission information.The acoustic emission amplitude,count,energy,and stress-time curve have better corresponding relationships during the loading on coal samples.The acoustic emission characteristics of coal sample after different high temperatures heating

关 键 词：岩石力学 高温后煤样 单轴压缩 变形强度 声发射特征 

分 类 号：TD313[矿业工程—矿井建设]