高温下砂岩动态力学特性研究

为研究高温下岩石的动态力学特性，组建了高温霍普金森压杆(SHPB)试验系统。并对处于不同温度等级（室温25～1 000 ℃）下的砂岩试件进行单轴动态压缩试验，研究了不同等级高温作用下砂岩峰值应力、峰值应变和弹性模量的变化规律。研究表明：砂岩动态力学特性的变化规律在100 ℃和200 ℃前后均发生了明显变化；200 ℃后砂岩峰值应力、弹性模量降低、峰值应变迅速增大；在高于600℃温度作用下砂岩动态力学特性较室温状态发生显著劣化。从材料的微观结构特征角度对高温下砂岩动态力学特性进行分析发现，不同温度等级高温对砂岩破坏的微观机理并不相同。研究成果可以为分析地下工程围岩在高温下的动态力学响应提供参考。

Research on Dynamic Mechanical Properties of Sandstone at High Temperature

A split Hopkinson pressure bar (SHPB) testing system was constructed to study the mechanical properties of sandstone at high temperature. The dynamic compression loading tests of sandstone with temperature rate varying from 25 ℃ to 1 000 ℃ were carried out to study the relationship among the dynamic mechanical properties, such as peak stress, failure strain, elastic modulus, and temperature. The experimental results show that the relationship of the mechanical properties of sandstone with the temperature changes sharply at 100 ℃ and 200 ℃.With the increase of temperature, the peak stress and the elastic modulus all gradually decrease, while the failure strain increases when the temperature is over 200 ℃. The mechanical properties deteriorate rapidly with the increase of temperature when the temperature is above 600 ℃. In the sight of microstructure characteristics of sandstone, the mechanical properties of sandstone at high temperature were analyzed. It is found that the micro mechanism that the destruction of high temperature to the sandstone changes sharply with the increase of temperature. The research conclusions can provide references for analyzing the dynamic mechanical behavior of the country rock of underground projects at high temperature.