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利用PXWAE型声发射系统进行了四点弯曲试验条件下页岩的声发射试验研究,试验中记录了岩样所受的最大弯曲应力、弯曲应变、声发射事件数、声发射能量等多个参数。研究发现,垂直页岩层理施加荷载时,在四点弯曲试验条件下其凯塞效应是存在的,凯塞点可以直接通过应力与累计声发射事件数曲线得出;但受自身水平层理结构及局部破坏的影响,应变在受载过程中会发生松弛现象,不易直接由应变-声发射试验曲线判断出岩石的凯塞点,必须结合其它试验数据以及岩样的最终破坏形态综合判断。弯曲应力状态下岩石的声发射特性研究对于利用声发射技术进行矿区顶板或隔层的稳定性监测具有一定的工程指导意义。
Acoustic emission experiment of shale under four-point bending test was carried out by PXWAE acoustic emission system. The parameters of maximum bending stress, bending strain, acoustic emission events, acoustic emission energy and other parameters . It is found that the Kaiser effect exists under the condition of four-point bending test when vertical shale bedding is applied, and the Kaiser point can be directly obtained by the curve of stress and cumulative AE events. However, due to its own horizontal bedding structure And local damage, the strain relaxation occurs during the loading process. It is not easy to determine the Kaiser point of the rock directly from the strain-acoustic emission test curve. Therefore, it must be combined with other experimental data and the final damage morphology of the rock sample. The acoustic emission characteristics of rocks under bending stress have certain engineering significance for the monitoring of the stability of roof or interlayer of mining area by acoustic emission technology.