基于声波技术感知煤自燃温度的方法具有应用场景广、实时连续性强等优势，但煤自燃过程中声波信号的前兆特征还未有揭示，进行煤自燃过程中声波效应和前兆特征的研究，为声波法探测预警煤自燃提供理论基础。首先理论分析煤岩热损伤破裂演化过程、声波传输特征，在此基础上建立了3种尺寸煤自燃声波信息测试系统，测试了煤升温及燃烧过程中次声波、声发射及声波声速信息，利用线性拟合、多重分形理论、傅里叶变换等方法，围绕声波信号的时序特征、与温度相关性、空间特征、非线性特征及频谱等方面进行分析，揭示煤自燃过程中声波信号前兆特征规律。结果表明：煤自燃过程中，随着温度升高，次声波声压值阵发性增长，声发射信号的振铃计数、能量值及声波声速与温度正相关；煤自燃前期次声波信号、声波声时变化更为明显，声发射信号在100 ℃之后的增大变化更显著；声波信号具有空间特征，随着热源距离增加，振铃计数、能量发生降低变化，温度升高不同距离下的声速值均不断增加，声速与温度拟合方程R²均超过0.9；煤升温过程中次声波、声发射信号具有多重分形特征并与煤自燃热破裂具有较好对应性；此外，煤升温过程中次声波主频发生迁移、主频幅值不断增加。最后对煤田高温异常区进行声发射测试，温度异常区域声发射信号变化明显。

The method of sensing coal spontaneous combustion temperature based on acoustic wave technology has the advantages of wide application scenarios and real-time continuity, but the precursor characteristics of acoustic wave signals in the process of coal spontaneous combustion have not yet been revealed. The study of acoustic effects and precursor characteristics in the process of coal spontaneous combustion provides a theoretical basis for the detection and warning of coal spontaneous combustion by acoustic wave method. The article firstly theoretically analyses the thermal damage rupture evolution process and acoustic wave transmission characteristics of coal rock. Three sizes of coal spontaneous combustion acoustic wave information testing systems were established to test the infrasound, acoustic emission and acoustic sound velocity information during coal heating and combustion. Using linear fitting, multiple fractal theory, Fourier transform and other methods, we analyse the temporal characteristics, temperature correlation, spatial characteristics, nonlinear characteristics and spectra of acoustic signals to reveal the precursor characteristics of acoustic signals in the process of spontaneous combustion of coal. The results show that with the increase of coal temperature, the infrasound sound pressure value increases paroxysmally, and the ringing counts, energy value and acoustic sound velocity of acoustic emission signals are positively correlated with the temperature. The infrasound signals and acoustic time changes were more obvious in the pre-coal spontaneous combustion period. The acoustic emission signal increases and changes more significantly after 100 ℃. The acoustic signal has spatial characteristics. With the increase of the distance from the heat source, the ringing count and energy change by decreasing. The speed of sound at different distances increases with increasing temperature, and the R² of the speed-temperature fitting equation exceeds 0.9. The infrasound and acoustic emission signals have multiple fractal characteristics during coal heating and correspond well with the thermal rupture of spontaneous coal combustion. In addition, the main frequency of infrasound waves migrated and the amplitude of the main frequency increased during the process of coal warming. Finally, the acoustic emission test was carried out in the high-temperature anomaly area of the coal field. The acoustic emission signals in the temperature anomalies change significantly.