含瓦斯原煤三轴压缩变形时的能量演化分析  

Analysis of energy evolution on gas saturated raw coal under triaxial compression

作　　者：滕腾[1] 高峰[1] 张志镇[1] 高亚楠[1] 

机构地区：[1]中国矿业大学深部岩土力学与地下工程国家重点实验室力学与建筑工程学院,江苏徐州221116

出　　处：《中国矿业大学学报》2016年第4期663-669,共7页Journal of China University of Mining & Technology

基　　金：国家重点基础研究发展计划(973)项目(2011CB201205);国家自然科学基金项目(51404250);江苏省自然科学基金项目(BK20140189);江苏省普通高校研究生科研创新计划项目(KYLX15_1409)

摘　　要：为了探究含瓦斯煤变形破坏过程中的能量演化规律,理论推导了恒定围压下含瓦斯煤样压缩变形时的能量计算公式.针对平顶山矿区八矿己15-14120工作面瓦斯突出煤体进行了4组不同瓦斯压力下的压缩破坏试验,得到了能量输入密度、弹性能密度和耗散能密度的演化规律.结果表明:1)含瓦斯煤三轴压缩变形破坏过程中,轴压方向能量吸收,围压方向能量释放,瓦斯压力做功与体应变有关.2)煤样达到峰值之前,能量输入密度、弹性能储存密度、能量耗散密度都随着轴向应力的增大而增大,吸收能密度最快,弹性能密度次之,耗散能密度增加缓慢;峰值过后,能量输入密度继续上升,弹性能密度下降,耗散能密度激增.3)基于声发射的能量释放规律与应力-应变曲线有很好的对应,瓦斯压力越大,相对于轴向应变的能量耗散来期越早,同时耗散速率也越快.4)随着瓦斯压力的提高,煤体变形声发射信号初始点、体积膨胀点、峰值应力点处的吸收能密度、弹性能密度降低,耗散能密度增大.Energy evolution of gas-saturated raw coal in the compression and failure process was studied based on a newly derived calculation method and a set of tests under constant confining and pore pressures. Tests on coal specimen with four different gas pressures from the 15-14120 working face in Pingdingshan mining area were carried out and the evolutions of input energy, elastic energy and dissipative energy were captured. The results show that coal absorbs energy in the axial direction, releases energy in the confining direction, releases （absorbs） energy due to the gas pressure in the whole volume when coal sample swells （shrinks）. The densities of input energy, elastic energy and dissipated energy all increase along with the increasing of axial stress in the pre-peak stage. However, the input energy density increases rapidly, the elastic energy density comes second and the dissipated energy density increases slowly. In the postpeak stage, the densities of input and dissipated energy continue to rise while the elastic energy density decreases. Energy releasing measured by the acoustic emission （AE） corresponds well to the stress-strain relation, the greater the gas pressure is performed, the earlier and faster the energy consumes. The densities of the input and elastic energy decrease with the increasing of gas pressure at the feature points of deformation while the density of dissipated energy increases.

关 键 词：原煤 瓦斯压力 能量演化 三轴压缩 声发射 

分 类 号：TU45[建筑科学—岩土工程]