温度对灰砂岩物理特征及抗拉强度影响的试验研究

为研究温度对灰砂岩物理特征及抗拉强度的影响,利用对径压缩试验对经历不同温度的灰砂岩圆盘试件的力学特性进行分析,结合动态信号测试分析系统实时监测并记录试件中部侧向应变,采用非金属超声检测分析仪、SEM等手段对经历不同温度的灰砂岩纵波波速、微观结构等特征进行表征。试验结果表明:1高温导致灰砂岩质量与纵波波速分别降低了3.83%与50.03%,损伤程度逐渐增大,且在经历温度为600℃时发生突变;2灰砂岩抗拉强度随经历温度的升高而减小,近似服从负线性分布,峰值压缩变形量与峰值侧向应变均随经历温度的升高而增大,在经历温度为600℃时发生突变;3高温导致试件颜色由灰白色变为淡黄色,断面起伏度降低,裂隙数量与裂隙类型增加。上述研究成果可以为热作用下地下结构稳定性的研究提供参考。

Experimental Investigation on the Effect of Temperature on Physical Characteristics and Tensile Strength of Grey Sandstone

In order to investigate the effect of temperature on physical characteristics and tensile strength of grey sandstone,radial compression experiment for gray sandstone disk specimen subjected to different high temperatures was carried out.Combined with dynamic signal testing and analysis system,the lateral strain in specimen's middle part was real-time monitored and recorded.By using non-metallic ultrasonic detecting instrument,SEM and other means,longitudinal wave velocity,microstructure characteristics of grey sandstone subjected to different high temperatures were characterized.Experimental results show that ① High temperature results in the longitudinal wave velocity and mass of grey sandstone decrease by 50.03 ％ and 3.83 ％ respectively,along with the rise of temperature,the damage degree of grey sandstone increases,meanwhile,both longitudinal wave velocity and mass change abruptly at temperature of 600℃.②The tensile strength of grey sandstone decreases along with the increase of temperature,which approximately presents negative linear distribution;with the increase of temperature,peak compression deformation and peak lateral strain decrease,and both change abruptly at temperature of 600℃.③High temperature results in sandstone color changes from gray white to light yellow,the waviness of cross section decreases,but the amount of crack and crack type increase with the temperature rising.Above results may provide reference for stability analysis of underground structure subjected to high temperature action.