掌握声发射信号时-频域特征及其与煤岩力学性质间的本质联系是利用该方法预测、预警煤岩失稳的基础。以具有不同夹矸和原始裂隙煤岩压缩破坏声发射监测试验为基础，引入小波变换方法，结合数字信号分析、岩石力学等相关理论深入分析煤岩破坏过程声发射时-频信号演化规律，构建了裂纹扩展释放弹性能引起应力波的振幅、频率力学表达。结果表明:受所含弱夹矸或裂隙增加影响煤岩强度、弹性模量降低，峰后软化特征明显，声发射存在由低幅振荡向高幅脉冲转化的信号激增点，强度越高，能量信号幅值显著提高、累积总能量越多，波形幅值增加，信号波形两相邻波峰间隔时间增长，夹杂的小幅振荡波越少;db5和sym2小波基函数分别与激增点、峰值点时域波形相似度最高，更适用于煤岩声发射信号研究;试验所用煤岩声发射信号主频带为0~70 kHz，煤岩强度越低信号频率分布越宽泛，随所受应力升高信号频带分布范围逐渐向主频移动。弹性模量和裂纹扩展速率共同确定了应力波振幅的变化范围，裂纹尺寸决定了振幅和频率的变化趋势，裂纹扩展速率是决定应力波频率的关键参量，进而三个参量共同影响声发射信号时-频特征。试验结果建立了裂纹表征参量与声发射信号频率、幅值的定性描述，为提高声发射信号监测准确性提供了理论基础，开展该理论的定量化的应用是后续研究工作的重点。

The time-frequency domain characteristics of acoustic emission signal and its essential relationship with mechanical properties of coal are the basis for predicting and warning the instability of coal. On the basis of acoustic emission monitoring test for the compressive failure of coal with different gangues and original cracks,the time-fre- quency domain evolution of acoustic emission signal is discussed in detail combined with digital signal theory,rock me- chanics and other related approaches,and the wavelet transform method is introduced. The mechanical expression of amplitude and frequency of stress wave is established,which is induced by elastic energy released from crack growth. The results showed that with the increase of weak gangue or crack in coal,its strength and elastic modulus decrease, the softening characteristic is obvious in the post-peak phase,and there is a signal surge point which transforms from a low amplitude oscillation to a high amplitude pulse of acoustic emission. The higher strength of coal,the higher the am- plitude of energy signal,the more cumulative total energy,the larger amplitude of waveform,the longer interval between the two adjacent peaks of signal waveform,and the fewer small oscillations mixed in the signal. The wavelet basis func- tions of db5 and sym2 have the highest similarity with the time-domain waveforms of the surge point and peak point re- spectively,which is more suitable for the study of acoustic emission signals of coal. The main frequency band of signal is 0-70 kHz,the lower loading stress level,the wider the signal frequency distribution,the signal band distribution gradually moves to the main frequency with the stress increase. The variation range of stress wave amplitude is deter- mined by elastic modulus and crack propagation rate,the crack size determines the variation trend of amplitude and frequency,crack propagation rate is a key parameter to determine the stress wave frequency,then three parameters af- fect the time-frequency characteristics of acoustic emission signals. The experimental results establish the qualitative description of crack characterization parameters with the frequency and amplitude of AE signal,which provides a theo- retical basis for improving the accuracy of AE monitoring method. Therefore,the quantitative application of the theory is the focus for the future research.