【作者】 左建平； 陈岩；

【Author】 ZUO Jian-ping;CHEN Yan;School of mechanics & civil engineering,China University of Mining and Technology;State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology;

【机构】 中国矿业大学(北京)力学与建筑工程学院； 中国矿业大学(北京)煤炭资源与安全开采国家重点实验室；

【摘要】 利用MTS 815试验机对深部煤岩组合体进行分级循环加卸载试验,获得其全应力-应变曲线,而后研究了加卸载过程中煤岩组合体轴向裂纹的闭合和张开效应,得出其轴向裂纹闭合应力(应变)和张开应力(应变)。研究结果表明:随着循环次数的增加,加载和卸载过程中煤岩组合体的裂纹闭合应力(应变)和张开应力(应变)具有增大的趋势;由于分级荷载的逐步增加,煤岩组合体产生新的裂纹,相对轴向裂纹闭合应变和相对轴向裂纹张开应变、轴向裂纹应力差随循环次数增大而增大;推导出轴向裂纹张开模型,并利用试验数据进行验证,计算得出的理论值与试验值吻合度较高,能够很好地描述卸载条件下轴向裂纹张开效应。研究结论有望丰富循环加卸载过程中煤岩组合体的破坏理论。更多还原

【Abstract】 Test machine MTS 815 was applied to carry out cyclic loading-unloading experiments for coal-rock combined body, and the complete stress-strain curves were obtained. Then, the axial crack closure and recovery effect was analyzed and the axial crack closure stress(strain) and recovery stress(strain). The results show that, the axial crack closure stress(strain) and axial crack closure recovery stress(strain) increase with increasing cyclic times. Due the increase of stress level, new cracks are generating, and the relative axial crack closure strain, axial crack recovery strain and axial crack stress difference increase with increasing cyclic times. Based on natural strain and engineering strain, the axial crack recovery model is proposed and verified by experimental data. The good agreement between theoretical data and test data shows the reasonable of this model. Also, the proposed model can describe the axial crack recovery effect during unloading process well. The conclusions may enrich the failure theory of coal-rock combined during cyclic loading-unloading process.更多还原