摘要
利用TAW-2000型电液伺服岩石力学试验系统开展了5种不同加载速率下的单轴压缩试验,分析了加载速率对煤体侧向变形特性的影响。研究结果表明:在裂纹闭合压密阶段、弹性变形至裂纹稳定扩展阶段,煤样变形以轴向压缩为主,侧向变形很小;在裂纹非稳定扩展阶段侧向应变开始加速增大,并在峰前应力调整阶段出现小幅陡增现象;在峰后扩容阶段煤样侧向应变急剧增大,呈现扩容与脆性破坏多次交替出现的特征,这一阶段大多数试件的侧向应变占总侧向应变的70%~90%。在加载初期煤样侧轴比处于较低水平,当轴向应力出现第一次跌落以后,煤样侧向应变快速增大,而轴向应变增加速度较小,导致试件侧轴比呈现快速增大直至试验结束。不同加载速率下煤样第一次出现轴向应力跌落时的侧向应变保持在3.0×10^-3左右,表明在不同加载速率下煤样出现第一次轴向应力跌落时的侧向应变基本相同,可将侧向应变作为预测煤体破坏的控制变量。
The uniaxial compression experiments were carried out using the TAW-2000 electro-hydraulic servo rock mechanical experimental system under five different loading rates, and the influence of loading rate on lateral deformation characteristics of coal is analyzed. The results of the study are as follows:(1)At the crack closure stage and elastic deformation to crack stable extension stage, the deformation of coal samples is mainly axial compression and the lateral deformation is small. At crack unstable extension stage, the lateral deformation begin to accelerate, and there is a slight steep increase in the pre-peak stress adjustment stage. The lateral deformation of the coal samples increases sharply, and the expansion and brittle failure occur alternately at the stage after the peak strength. At this stage, the lateral strain of most coal samples accounts for 70% to 90% of the total lateral strain.(2)The lateral-axis ratio of coal samples is at a relatively low level at the initial stage of loading. After the first fall of the axial stress, the lateral strain of the coal sample rapidly increases, while the axial strain increases slowly, resulting in a rapid increase of the lateral-axis ratio until the end of the test.(3)The lateral strain is maintained at 3.0×10^-3 when the axial stress falls for the first time at different loading rates. It shows that the lateral strain of coal samples under different loading rates is basically the same when the first axial stress fall occurs, and the lateral strain can be used as the control variable to predict the coal body damage.
作者
马振乾
梁旭超
池恩安
张鹏冲
谢雄刚
Ma Zhenqian;Liang Xuchao;Chi Enan;Zhang Pengchong;Xie Xionggang(School of Mining,Guizhou University,550025,Guiyang,China;Baoli Xinlian Blasting Engineering Limited Company,550002,Guiyang,China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining&Technology,100083,Beijing,China;China Coal Technology Engineering Group Chongqing Research Institute,400037,Chongqing,China)
出处
《应用力学学报》
CAS
CSCD
北大核心
2020年第5期2007-2012,I0012,共7页
Chinese Journal of Applied Mechanics
基金
国家自然科学基金(51904080)
中国博士后科学基金(201864M1525)
贵州省基础研究计划项目(黔科合基础[2019]1116)
贵州省科技支撑计划项目(黔科合支撑[2020]2Y026)。
关键词
加载速率
侧向变形
煤体
单轴压缩
loading rate
lateral deformation
coal
uniaxial compression
