基于小波包变换的不同强度煤样的声发射特性

Acoustic emission characteristics of coal samples with different strength based on wavelet packet transform

为了研究在单轴压缩下不同强度煤样的声发射特征,利用RMT-150C型岩石力学伺服试验系统和CDAE-1型声发射检测仪,对硬煤、中硬煤和软煤煤样进行实验研究。为了解决煤样在声发射实验中存在的各种信号干扰和信号处理方面的问题,运用小波包变换对煤样的声发射信号进行了分解、去噪和重构。研究结果表明:经过处理之后的声发射信号能够更清晰地反映硬煤、中硬煤和软煤煤样在单轴压缩下失稳破坏的变化特征。软煤、中硬煤和硬煤的声发射信号特征各不相同,随着煤样强度的增加,煤样失稳破坏时声发射累计能量和累计计数逐渐减小,煤样在受力过程中声发射能量和计数的峰值也逐渐减小,并且在峰值处释放的能量也逐渐减小。

In order to study acoustic emission characteristics of coal samples with different strength under uniaxial compression, experimental study of hard coal, medium hard coal and soft coal was carried out by using RMT-150C rock mechanic test system and CDAE-1 acoustic emission instrument. In order to solve the problems of different interference noise and signal processing in the acoustic emission test, decomposition, de-noising and reconstruction for the acoustic emission signals were conducted through wavelet packet transform. The results show that the processed acoustic emission signals can more clearly reflect the variation characteristics of buckling failure under uniaxial compression. Soft coal, medium hard coal and hard coal have different acoustic emission characteristics. With the increase of coal strength, acumulative energy and acumulative counts of acoustic emission decrease gradually at the instability failure, energy and count peak of acoustic emission of coal samples also decrease under stress, and the released energy at the peak decreases too.