高温后大理岩力学性质及其破坏规律研究

STUDY ON FAILURE MECHANICAL BEHAVIOR OF MARBLE AFTER HIGH TEMPERATURE

  • 摘要: 基于大理岩在常温至高温800℃后的力学试验结果,分析了高温后大理岩峰值强度、峰值应变、弹性模量、变形模量以及应力-应变全过程曲线等随温度的变化规律,同时采用岩石声发射仪与扫描电镜试验仪,对高温后大理岩破坏规律进行了探讨。结果表明:高温后大理岩试样高度和直径将变大,质量和密度减小,但在200℃时变化不明显;在常温至高温200℃后,大理岩的力学性质变化不大;高温400℃~800℃,大理岩峰值强度、弹性模量和变形模量随着温度的升高而减小,而峰值应变则变大,并且随着温度的升高,变化越明显;声发射试验得到的振铃计数与应力-时间曲线具有较好地对应关系,充分反映了岩石在不同阶段内的破裂演化规律;温度对大理岩的破坏规律有着显著影响,温度升高使大理岩由脆性破坏向延性破坏的方向发展。

     

    Abstract: Laboratory tests were made to study the mechanical properties of marble from room temperature of 800℃. The changes of peak intensity, peak strain,the modulus of elasticity, the modulus of the deformation and complete stress-stain curve of marble after high temperature were analyzed in detail. An acoustic emission instrument and a scanning electron tester were used at the same time. The failure law of marble after high temperature was studied. The results showed that the length and diameter of a marble specimen after high temperature increase, the mass and density decrease, but change little at 200℃ ; The mechanical properties of marble change little when the temperature keeps to 200℃; The peak intensity, the modulus of elasticity and deformation modulus of marble decrease and peak strain becomes large as the temperature increases when the temperature is between 400℃ to 800℃, the changes became more obvious as the temperature increase; The ringing count of the acoustic emission has a good corresponding relationship with a stress curve, which fully reflects the rupture evolution law of marble in different stages; Temperature has a significant effect on the destruction law of marble, as temperature rise, the failure of marble is from brittle failure to ductile failure .

     

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