单轴加载条件下砂岩声发射特性分析

通过单轴加载条件下砂岩破裂过程的声发射试验,采集了砂岩变形各个阶段的声发射信号,得到了应力-时间-累计振铃计数、应力-时间-声发射事件率曲线.结合应力-应变曲线,对整个破坏过程中的声发射信号特征参数进行了分析,同时采用快速傅里叶变换,对其中按时间序列选取的110个声发射信号进行了频谱分析,得到了声发射信号对应的主频,对主频随应力的变化情况进行了分析.结果表明:在峰值强度50%之前,主频随压力随机变化,在峰值强度50%之后主频有降低的趋势,且主频主要集中在140~180 kHz之间.

Acoustic emission characteristics analysis of sandstone under uniaxial compression

Through the acoustic emission experiment of sandstone under uniaxial load, the Acoustic Emission sig- nals of sandstone in various deformation phases by obtaining the curves of stress-time-ring accumulative count and stress-time-AE rates are collected. Combined with the stress -strain curve, the characteristic parameters of AE in the whole failure process are analyzed. Through the FFT （Fast Fourieer Transform）,the amplitude spectrum of 110 AE events selected by time sequence are discussed retaining the dominant frequency of AE signals. The changes of the dominant frequency with stress are also discussed. The results show that the dominant frequency changed randomly when the stress level is lower than 50 % of the peak stress. Subsequently, the dominant fre- quency has the tendency to reduce and the dominant frequency mainly ranges between 140 kHz to 180 kHz.