摘要
利用声发射事件率、振铃事件比和累计振铃数作为AE表征参数,进行单轴受压下突出煤样破坏全过程声发射试验。试验结果表明,不同轴向载荷的作用过程中,煤样声发射特征变化具有阶段性,根据全应力–应变曲线和声发射特征的变化规律均可分为5个阶段;因既反映声发射事件发生的频度又涉及事件的能量,声发射振铃事件比能更为准确地反映煤体变形破坏过程中声发射变化趋势,适合作为煤岩动力灾害预测的主要参数之一。弹塑性阶段是累计振铃数增长的主要阶段,累计振铃数达到AE累计振铃总数的35.35%;在接近峰值强度时,AE累计振铃数曲线趋于平缓,出现声发射相对平静期,即在其他岩石中存在的峰前相对平静期也存在于具有较多原始损伤的煤体之中,但损伤煤体的相对平静期更短,AE累计振铃数曲线突增和峰前相对平静期可作为煤样峰值破坏的征兆用于煤与瓦斯突出预测预报。
Acoustic emission（AE） characteristics of outburst coal samples are studied during the failure process in uniaxial compression under the stiffness test machine（MTS）.The AE rate,ringdown-event ratio,cumulative counts,stress-strain levels,time and the relations among them are also analyzed.The results show that AE characteristics of coal samples depend strongly on different failure phases during the loading process of compressive tests,and the failure process is divided into five phases according to stress-strain curves and AE characteristics.The ringdown-event ratio is related to the change of energy in the coal,which represents the trend of AE curves during the failure process more accurately.So it can be used as one of the main forecasting parameters of coal and rock dynamic catastrophe.Elastoplastic phase（III） is the main phase,in which AE accumulative counts increase more,about 35.35% of its total counts.When the stress-strain curve is near the peak,the AE accumulative counts curve reaches a plateau,which means that there is a relatively inactive period of AE.The pre-peak relatively inactive period in other rocks also exists in the originally damaged coal,but the period of the damaged coal is shorter.The sharp increment of AE curves and the relatively inactive period before peaks can be seen as the symptoms of the coal peak value destruction to forecast the coal-gas-outburst in the coal mine.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2007年第A01期2794-2799,共6页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(50674111)
重庆大学2005年大学生创新基金资助项目
关键词
采矿工程
声发射
突出煤体
单轴压缩
应力状态
破坏机制
mining engineering
acoustic emission（AE）
outburst coal
uniaxial compression
stress state
failure mechanism
