煤样单轴压缩破坏红外温度临界慢化前兆研究

为研究煤样受载破坏过程中有效前兆信息,开展了煤样单轴压缩加载试验,分析了在相同加载方式下煤样红外辐射温度变化特征,运用临界慢化理论对煤样最高红外辐射温度进行处理,比较了最高红外辐射温度的方差和自相关系数,分析了方差、最高红外辐射温度以及载荷在时间上的变化特征。结果表明:煤样在受载前期和中期最高和平均红外温度变化趋势基本保持一致,受载后期最高红外温度在煤样损伤点处呈上升趋势,主破裂发生时,最高红外辐射温度急剧上升,而平均红外温度在主破裂时并未表现出明显变化;方差和自相关系数均受窗口长度和滞后步长的影响,但方差曲线受窗口长度影响较大;对比红外降温前兆点和红外升温突增点,方差对煤样失稳破坏的预测更加的精准。

Study on Precursor of Infrared Temperature Critical Slowing in Coal Sample Uniaxial Compression Failure

To study the effective precursor information of the coal sample under loading and damage process,we carried out the uniaxial compression loading experiment of coal sample,analyzed the infrared radiation temperature variation characteristics of the coal sample under the same loading mode,and applied the critical slowing theory to the highest infrared radiation of the coal sample.The temperature was processed,the variance and autocorrelation coefficient of the highest infrared radiation temperature were compared,and the variance,the highest infrared radiation temperature and the variation of the load in time were analyzed.The results show that the highest and average infrared temperature trends of coal samples in the early and middle loading period are basically the same.The highest infrared temperature in the late stage of loading shows an upward trend at the damage point of coal samples.When the main rupture occurs,the highest infrared radiation temperature rises sharply.The average infrared temperature did not show significant changes at the main rupture;the variance and autocorrelation coefficients were affected by the window length and the lag step,but the variance curve was greatly affected by the window length;the contrast infrared precipitation precursor and the infrared temperature rise the increase point,the variance is more accurate in predicting the instability of coal samples.