瓦斯与应力作用下煤体红外辐射响应研究

Infrared radiation response of coal under the action of gas and stress

为探索瓦斯与应力作用下煤体红外辐射响应特征,利用自主研发的含瓦斯煤岩破裂温度变化检测实验系统,以平煤十一矿煤样作为研究对象,分析其在不同瓦斯压力下力学性质和红外辐射特性,并对差分最高辐射温度ΔTMIR、累计差分温度ΣΔTMIR、热像演化等在不同瓦斯压力下的时变特性进行对比分析。结果表明:随着瓦斯压力的增大,试样破坏形态从单斜面剪切破坏向剪张性失稳破坏转变,破坏发展明显增强;试样的峰值抗压强度、弹性模量随着瓦斯压力的增大而降低,峰值应变表现为先增加后快速降低;不同瓦斯压力下,试样整体上表现出增温趋势,低瓦斯压力(0~0.4 MPa)条件下临破裂前出现升温前兆,而高瓦斯压力(0.6,0.8 MPa)则表现为降温前兆;试样加载过程中出现低温异常条带和高温异常区域,且与宏观裂纹走向及位置一致;并揭示了瓦斯影响下煤岩红外辐射的响应机制:热弹效应、摩擦热效应、瓦斯膨胀吸热效应及吸附瓦斯解吸吸热效应,不同加载阶段热效应的影响程度不同。研究结果解释了煤岩瓦斯动力灾害温度异常变化的原因,明确了不同瓦斯压力下的红外预警前兆特征,可以根据矿井瓦斯压力的大小有针对性进行灾害监测预警。

To explore the characteristics of the infrared radiation response of coal bodies under the action of gas and stress,the self-developed experimental system for detecting the temperature change of gas-bearing coal rock rupture was used to analyze the mechanical properties and infrared radiation characteristics of coal samples from Pingcoal Mine 11th under different gas pressures,and to compare the time-varying characteristics of differential maximum radiation temperatureΔTMIR,cumulative differential temperatureΣΔTMIRand thermal image evolution under different gas pressures.The comparative analysis of the time-varying properties of differential maximum radiation temperatureΔTMIR,cumulative differential temperatureΣΔTMIRand thermal evolution at different gas pressures were carried out.The results show that,with the increase of the gas pressure,the damage pattern of the specimens changes from single-slope shear damage to shear-tension instability damage,and the damage development increases significantly.The peak compressive strength and the elastic modulus of the specimens decrease with the increase of the gas pressure,and the peak strain shows an increase and then a rapid decrease.The specimens show an overall warming trend at different gas pressures,with a warming precursor before rupture at low gas pressures(0–0.4 MPa)and a cooling precursor at high gas pressures(0.6 and 0.8 MPa).The low-temperature anomalous stripes and high-temperature anomalous regions appear during loading of the specimens and are consistent with the macroscopic crack orientation and location.The response mechanisms of infrared radiation from coal rocks under the influence of gas are revealed,including thermoelastic effect,frictional heat effect,gas expansion heat absorption effect,and adsorbed gas desorption heat absorption effect,with different degrees of influence of the thermal effect at different loading stages.The results of the study explain the causes of abnormal temperature variations of coal rock gas dynamic disasters and clarify the characteristics of infrared warning precursors under different gas pressures,which can be used for targeted disaster monitoring and warning according to the magnitude of gas pressure in mines.