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为了得到高温高应力下岩石的动态力学性能,对其进行冲击加载实验。对SHPB实验系统进行改进,使该系统能够实现温度与轴压共同作用下的冲击加载实验。采用扫描电子显微镜观察花岗岩碎片的内部结构特征。研究结果表明:花岗岩的纵波波速随温度的升高呈下降趋势,先快速后缓慢下降;花岗岩的单轴动态抗压强度随温度的升高呈下降趋势,其值在25~100°C比在100~300°C时下降得更加明显;峰值应变则随温度的升高而逐渐增大,同样以100°C为分界点,先快速后缓慢增加;随着温度的增加,花岗岩内部发生了巨大的变化,如原生裂纹和新生裂纹的扩展和贯通。另外,轴压下的热损伤比以波速表征的热损伤大,特别是随着温度的增加,这种现象更加明显。
In order to obtain the dynamic mechanical properties of rock under high temperature and high stress, the impact loading experiment was carried out. The SHPB experimental system is improved so that the system can perform shock loading experiment under the effect of temperature and axial pressure. Scanning electron microscopy was used to observe the internal structure of granite fragments. The results show that the longitudinal wave velocity of granite decreases with the increase of temperature, and then decreases slowly firstly. The uniaxial dynamic compressive strength of granite decreases with the increase of temperature, 100 ~ 300 ° C when the decline is more obvious; peak strain increases with temperature gradually increased, the same to 100 ° C as the cut-off point, the first rapid increase slowly; with the increase of temperature, a huge internal granite occurred Changes such as the expansion and penetration of native and newborn cracks. In addition, thermal damage under axial compression is greater than thermal damage characterized by wave velocity, especially as the temperature increases.