煤岩破裂过程中应力对红外辐射的控制效应试验
Experimental study on dependence of infrared radiation on stress for coal fracturing process
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摘要: 煤岩破裂是引发突水与煤柱失稳等矿山灾害的根本原因,准确有效地对煤岩受力破裂过程(裂隙发育过程)进行监测预警,是实现矿山保水开采和岩层控制的重要基础。煤岩在受力破裂过程中,伴随着应力调整会发生红外辐射变化,为探索应力变化与红外辐射变化之间的量化关系,提出煤样表面红外辐射方差突变系数新指标,进行煤单轴加载红外辐射观测实验研究。研究结果表明,应力对单轴加载煤样的红外辐射普遍具有控制效应,50 mm×50 mm×50 mm煤样表现出控制效应的比例约为93%;50 mm×50 mm×100 mm煤样表现出控制效应的比例约为85%。在红外辐射试验中,煤样表面红外辐射方差突变系数平均达到煤样应力调整系数的2个数量级,可运用此特征对承载煤岩体裂隙发育及破裂状况进行红外实时监测。同时,应力对红外射的控制效应具有时间滞后性,50 mm×50 mm×50 mm煤样的红外辐射方差突变平均滞后其应力调整时刻约2.7 s,50 mm×50 mm×100 mm煤样的红外辐射方差突变平均滞后其应力调整时刻约2.9 s。Abstract: Coal rock fracture is the major factor of disasters which occurred because of mine water bursting and the un- stability of coal pillar. Effectively supervising the process of it is extremely important to the water conservation and stra- ta control in mine. It is known that infrared radiation changes with the stress when coal rock is loading. The sudden change index of the variance of infrared radiation temperature of coal under uniaxial compressive loading was proposed to study the quantitative relationship between stress and infrared radiation. The result of this study shows the ratios of IR controlled by stress in cubic coal specimens (50 mm×50 mm×50 mm) and rectangular coal specimens were 93%and 85% . Sudden change coefficient of the variance of infrared radiation temperature which occurs after stress adjust- ment is two orders of magnitude than the coefficient of stress adjustment. Also this control effect has a characteristic of hysteretic,the average hysteretic time of infrared radiation of cubic coal specimens and rectangular coal specimens were about 2. 7 s and 2. 9 s.
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