单轴压缩条件下砂岩的声热效应特征研究
Study on the characteristics of the acoustic and the thermal effects of sandstone under uniaxial compression condition
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摘要: 在单轴压缩条件下对鄂尔多斯盆地煤系地层中的中砂岩、细砂岩、粉砂岩进行声发射 (AE)和红外辐射测试,分析加载过程中应力、声发射能量、平均红外温度(AIRT)与时间演化特 征,研究不同颗粒砂岩在破裂过程中的声热效应特征。 结果表明:同种砂岩不同区域AIRT在压 密弹性阶段走势相同,在塑性及破坏阶段走势并不一致,总体呈波浪下降趋势,且砂岩中部的温 度均高于上部和下部;不同砂岩破坏时温度变化与能量积聚、耗散状态相关,表面整体AIRT变化 呈现波浪下降趋势;AE刚开始不明显,塑性阶段后期AE由相对平静状态进入突增状态,峰后仍 有大量AE现象;红外辐射的前兆要先于AE,中砂岩的红外预警时间平均比AE提前20*533s, 细砂岩提前6*516s,粉砂岩提前6*4s,AE敏感性要高于红外辐射;砂岩的声热效应与颗粒大小 密切相关,颗粒越大,声热效应越明显,依次为中砂岩、细砂岩、粉砂岩。Abstract: Acousticemissionandinfraredradiationmeasurementswerecarriedouton medium sand⁃ stone,finesandstoneandsiltstoneinthecoalmeasuresoftheOrdosBasinunderuniaxialcompression, thestress,theacousticenergyandtheaverageinfraredradiationtemperature(AIRT)versustimeevo⁃ lutionofcharacteristicswereanalyzed,theacousticandthethermaleffectscharacteristicsofdifferent granularsandstonesduringtheruptureprocesswerestudied*TheresultsshowthattheAIRTinthedif⁃ ferentareasofthesamesandstonehasthesametrendinthecompactionandelasticityphase,butthe tendencyisdifferentintheplasticityanddamagestages*Itgenerallyshowsawavedownwardtrend;and thetemperatureinthemiddleishigherthanthatintheupperandlowerparts*Thetemperaturechanges indifferentsandstonesarerelatedtoenergyaccumulationanddissipation,andtheoveralltrendofAIRTonthesandstonesurfaceshowsawavedownwardtrend,acousticemission(AE)isnotobviousatthe beginning,butitraiserapidlyduringthelaterstageofplasticity,therearestillalargenumberofAEe⁃ ventsafterthepeak;theprecursorofinfraredradiationprioritytotheacousticemissionwarning,the averageinfraredwarningtimeofmiddlesandstoneis20*533s,finesandstoneis6*516sahead,and siltstoneis6*4s,butthesensitivityoftheacousticemissionishigherthanthatoftheinfraredradia⁃ tion*Theacousticandthethermaleffectsofsandstoneiscloselyrelatedtotheparticlesize,thelarger theparticles,themorepronouncedtheacousticthermaleffects*Thesensitivityoftheacousticthermal effectisintheorderofmediumsandstone,finesandstoneandsiltstone*