煤样三轴卸荷破坏的能量演化特征试验分析  

Experimental research on energy evolution properties of coal sample failure under triaxial unloading testing

作　　者：杨永杰[1] 马德鹏 YANG Yongjie;MA Depeng(State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology,Shandong University of Science and Technology,Qingdao,Shandong 266590,China;School of Water Conservancy and Civil Engineering,Shandong Agricultural University,Tai'an,Shandong 271018,China)

机构地区：[1]山东科技大学矿山灾害预防控制省部共建国家重点实验室培育基地,山东青岛266590 [2]山东农业大学水利土木工程学院,山东泰安271018

出　　处：《采矿与安全工程学报》2018年第6期1208-1216,共9页Journal of Mining & Safety Engineering

基　　金：国家重点研发计划项目(2018YFC0604705);国家自然科学基金项目(51574156);山东省高等学校科研计划项目(J18KA195);重庆市教委科学技术研究项目(KJ1732439)

摘　　要：煤样变形破坏方式与其能量转化密不可分,为探求煤样破坏过程中能量的演化规律,对其进行了不同试验路径的加、卸荷试验。试验结果表明:不同试验路径下,煤样在峰值应力前以能量的存储及耗散为主,在峰值应力后以能量的释放及耗散为主;能量耗散使得其内部裂隙扩展,造成煤样损伤劣化,承载能力下降,能量释放使其发生破裂失稳;三轴卸围压试验中,卸荷初始围压越高,煤样存储的弹性能越多,破裂时释放的能量也越多,使得高围压下煤样破坏更为剧烈。因此,高应力煤岩体在开挖卸荷时,极易引起大量的弹性能急剧释放,导致冲击地压、岩爆等灾害发生。此外,在三轴卸围压试验中,由于围压的卸荷效应,煤样临近破裂时损伤曲线的突变程度与常规三轴压缩相比更加明显,也可以看出卸荷破坏相比加荷破坏更具突发性。The deformation and failure of coal sample are closely relative to the energy transformation, in order to explore laws of energy evolution in the process of coal sample damage,the loading and un- loading testing under different testing paths are carried out.Based on experimental results,before the peak stress,it is mainly dependent on the energy storage and dissipation.After peak stress,it is mainly dependent the energy release and dissipation in different testing paths.The energy dissipation causes the internal crack extension,which leads to the coal sample damage and lithologic deterioration.The coal sample's bearing capacity reduces,while the energy conversion is the internal cause for the coal rock tensile fracture.In the triaxial unloading confining pressure testing,the higher the initial unloading confining pressure is,the more elastic energy storage and the more energy are released when the coal sample is failure.The damage is more severe under the high confining pressure.Therefore,it is easy to cause a lot of elastic energy releasing sharply during the excavation of high stress coal rock mass.It leads to impact the ground pressure and the rock burst disasters.In addition,due to the unloading effect of confining pressure in the triaxial unloading testing,the damage curve mutation degree is more obviously approaching the rock burst comparing to conventional triaxial compression testing.It can be seen that the unloading damage is more abrupt comparing with loading damages.

关 键 词：煤样 卸围压 能量 损伤 三轴压缩 

分 类 号：TD353[矿业工程—矿井建设]