温度对大理岩力学性质影响的细观研究

Microstructural investigation of mechanical characteristics of marbles under different temperatures

对不同温度下的大理岩进行单轴压缩试验,结果表明,经过高温后大理岩单轴抗压强度和弹性模量都大幅度降低,阈值温度在100℃左右.采用扫描电镜对各温度下大理岩断口进行扫描并对SEM图像进行了分析,对得到的不同温度下微裂隙的长度、方位角、间距等参数进行了统计分析,得到了细观结构几何参数在不同温度下的分布概型：长度在温度20-300℃时服从对数正态分布,450-600℃时服从Weibull分布;方位角在不同温度下服从正态分布;间距在温度20-300℃时服从对数正态分布,450-600℃时服从指数分布.

Uniaxial compression tests of marbles under different temperatures were conducted. The results show that the uniaxial compression strength and elastic modulus of the heated rock decreases dramatically, and the threshold temperature of marbles is about 100℃. Using scanning electron microscopy （SEM）, the fracture microstructure of marbles under different temperatures was examined. From the SEM images, the microcracks＇ microstructural parameters, including length, azimuth angle and spacing, were obtained and statistically analyzed. The lengths of the microcracks fit log-normal distribution from 20℃ to 300℃ and Weibull distribution from 450℃ to 600℃, the azimuth angles fit normal distribution in any temperature range, and the microcracks＇ spacing fits logarithmic normal distribution between 20℃ and 300℃ and exponential distribution between 450℃ and 600℃.