高温下大理岩的声发射特性试验研究
Acoustic emission characteristics of thermal cracking of marble under uniaxial compression
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摘要: 为探讨温度对岩石声发射特性的影响,在20℃~800℃实时高温下及400℃~800℃高温作用冷却后两种情况下对徐州大理岩进行了单轴压缩和声发射试验。研究结果表明:加温过程中,大理岩产生了强烈的声发射信号,且随着温度的升高而趋于活跃;高温单轴压缩过程中,大理岩的声发射振铃计数率逐渐趋于密集,在临近破坏时声发射活动异常活跃,并且声发射率在岩样破坏时达到最大值;400℃、600℃、800℃高温下徐州大理岩在加载过程中的声发射活动比其对应高温后的更频繁;800℃高温作用下,大理岩岩样在达到峰值强度后出现明显的塑性变形,此变形阶段岩石的声发射信号明显下降,出现相对平静的现象。Abstract: To investigate the influence of temperature on the characteristics of acoustic emission of rock, the uniaxial compression and acoustic emission tests are conducted on Xuzhou marble at real-time high temperatures(20℃~800℃)and after high temperatures (400℃~800℃). The results show that the marble specimens produce strong acoustic emission signals and become more active as temperature rises in the heating process. The acoustic emission ringing count rate of marble gradually tends to dense, and acoustic emission activity becomes very active near the destruction of samples which reaches the maximum when marble specimens are damaged in the loading process at high temperature. The acoustic emission activity of marble is more frequently at high temperature of 400℃, 600℃ and 800℃ than that after high temperature. The plastic deformation occurs after reaching the peak intensity of marble specimens in which the acoustic emission rate significantly reduces and relatively calm phenomenon appears.