| 引用本文: | 鲁细根,纪洪广,余小妹,蒋华,高宇,吴浩源.三轴卸荷条件下煤体力学特性和能量耗散演化[J].哈尔滨工业大学学报,2022,54(2):90.DOI:10.11918/202011057 |
| LU Xigen,JI Hongguang,YU Xiaomei,JIANG Hua,GAO Yu,WU Haoyuan.Mechanical characteristics and energy dissipation evolution of coal under triaxial unloading[J].Journal of Harbin Institute of Technology,2022,54(2):90.DOI:10.11918/202011057 |
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| 三轴卸荷条件下煤体力学特性和能量耗散演化 |
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鲁细根1,纪洪广1,余小妹2,蒋华3,4,高宇,1,吴浩源1
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(1.北京科技大学 土木与资源工程学院,北京 100083;2.南昌工学院 人居环境学院,南昌 330108; 3.青岛国信建设投资有限公司,山东 青岛 266061;4.青岛国信胶州湾第二海底隧道有限公司,山东 青岛 266061)
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| 摘要: |
| 孤岛工作面煤体和巷道受周边开采扰动影响,煤体受循环荷载作用存在卸荷力学行为而表现出动态破坏特性。为探讨不同路径下煤体力学特性,利用TAW-2000三轴电液伺服刚性试验机分别进行常规三轴(T)、三轴循环荷载(TC)以及相应卸围压试验(TU、TCU),分析不同围压下煤体卸围压强度、变形、声发射事件以及能量耗散演化特征,开展扰动区域煤体卸荷特性研究。结果表明:三轴循环荷载卸围压(TCU)下拟合回归强度低于常规三轴卸围压(TU)下拟合回归强度,高于三轴循环荷载(TC)下拟合回归强度；卸围压(TU、TCU)应力路径下声发射峰值滞后应力峰值,AE振铃计数在煤样破坏点突增,高于常规三轴(T、TC)数值；循环过程(TC、TCU)中应力水平达到峰值强度的70%时,Kaiser效应逐渐消失,Felicity效应出现；循环加卸载(TC)试验中,相对应力水平达到60%,煤样损伤加剧,弹性应变能占比逐渐减小；围压越大,煤样破坏时冲击能指数越小,三轴循环荷载(TC)冲击能指数<常规三轴(T)冲击能指数<三轴循环荷载卸围压(TCU)冲击能指数<常规三轴卸围压(TU)冲击能指数；围压对煤样有横向束缚作用,减弱冲击能释放速率,降低煤样破碎程度。 |
| 关键词: 三轴循环荷载 卸围压 能量耗散 声发射 破坏特征 |
| DOI：10.11918/202011057 |
| 分类号:TU45 |
| 文献标识码:A |
| 基金项目:国家自然科学基金重点项目(51534002)；国家重点研发计划项目(2016YFC0600801)；国家自然科学基金(52004015)；北京市自然科学基金(2204084) |
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| Mechanical characteristics and energy dissipation evolution of coal under triaxial unloading |
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LU Xigen1,JI Hongguang1,YU Xiaomei2,JIANG Hua3,4,GAO Yu1,WU Haoyuan1
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(1.School of Civil and Resources Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2.School of Human Settlements and Civil Engineering, Nanchang Institute of Science and Technology, Nanchang 330108, China; 3.Qingdao Guoxin Construction Investment Co., Ltd., Qingdao 266061, Shandong, China; 4.Qingdao Guoxin Jiaozhou Bay Second Subsea Tunnel Co., Ltd., Qingdao 266061, Shandong, China)
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| Abstract: |
| The coal and roadway of isolated island working face are affected by surrounding mining disturbance, and the unloading confining pressure of coal mass shows dynamic failure characteristics under cyclic loading and unloading. In order to explore the mechanical characteristics of coal under different load paths, the conventional triaxial (T), triaxial cyclic load (TC), and corresponding unloading confining pressure (TU, TCU) tests were carried out by TAW-2000 three-axis electro-hydraulic servo rigid testing machine. The strength, deformation, acoustic emission (AE) events, and energy dissipation characteristics of coal under different confining pressures were analyzed. Research on the unloading characteristics of coal in disturbed area was carried out. Results show that the strength of fitting regression under TCU was lower than that under TU, higher than that under TC. Under the stress path of unloading confining pressure (TU, TCU), the AE peak value lagged behind the stress peak value, and the AE ringing counts increased sharply at the failure point of coal sample, which was higher than that under conventional triaxial (T, TC). During the cycle processes (TC, TCU), when the stress level reached 70% of the peak strength, Kaiser effect gradually disappeared and Felicity effect appeared. In the cyclic loading and unloading (TC) test, the relative stress level reached 60%, the damage of coal sample was aggravated, and the proportion of elastic strain energy decreased gradually. The larger the confining pressure was, the smaller the impact energy index was; the order of impact energy index from small to large was: triaxial cyclic load (TC)
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| Key words: triaxial cycle unloading confining pressure energy dissipation acoustic emission failure characteristics |
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