标题：Acoustic emission characteristics of coal creep under step load
作者：Yang, Yongjie ;Wang, Dechao ;Zhao, Nannan ;Chen, Shaojie
作者机构：[Yang, Yongjie ;Wang, Dechao ;Zhao, Nannan ;Chen, Shaojie ] State Key Laboratory Cultivation Base of Mining Disaster Prevention and Control, Shandong 更多
来源：Yingyong Jichu yu Gongcheng Kexue Xuebao/Journal of Basic Science and Engineering
关键词：Acoustic emission; Coal; Creep; Damage evolution; Step load; Stress threshold
摘要：Experiments on acoustic emission (AE) characteristics of coal specimens under step load were carried out with MTS815 servo-controlled rock mechanical test system and AE21C detection system. Analysis of the experimental results showed that the step load had a creep stress threshold, creep deformation was not obvious until the loading exceeds the threshold. During the transient creep stage, AE activities gradually increased with the expending of the micro-pores and micro-fractures inside coal. During the steady creep stage, the creep deformation rate tended to be stabilized and the new fractures were less, and the AE events were less and their energy was low. During the accelerated creep stage, a large number of new fractures occur and quickly develop and cause the coal specimen to the macro fracture failure, the stored energy quickly released in a short period of time. Simultaneously, the AE events and their energy reached to the maximum value. The creep damage evolution process of coal can be well reflected by AE characteristics.