To study the effect of temperature on the dynamic mechanical behaviors and fracture characteristics of thermally treated sandstone, compressive dynamic loading experiments were performed on a series of samples using a split Hopkinson pressure bar (SHPB). In the tests, the dynamic uniaxial compressive strength of the thermally treated sandstone was inversely proportional to the temperature treatment in the range of 200°C–1000°C, while the dynamic elastic modulus first increased and then gradually decreased after different temperature treatments. The results show that two classical mechanical types (i.e., Class I and Class II) are observed from the dynamic stress-strain responses of SHPB tests for thermally treated sandstone. By means of scanning electron microscopy (SEM), the microdifference of postloading microfracture characteristics in Class I and Class II behavior was identified. In Class I behavior, intercrystalline cracks (IE) are the chief form of cracks on the fracture surface of a specimen fractured by SHPB loading even though there some intracrystalline cracks may also be present. In contrast, Class II behavior results from the chief cracking type being intracrystalline cracks.

中文翻译：

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SHPB冲击荷载下热处理砂岩多尺度压裂试验研究

为了研究温度对热处理砂岩的动态力学行为和断裂特性的影响，使用分裂式霍普金森压力棒 (SHPB) 对一系列样品进行了压缩动态加载实验。试验中，热处理砂岩的动态单轴抗压强度在200℃～1000℃范围内与温度处理成反比，而动态弹性模量在不同温度处理后先增大后逐渐减小。结果表明，从热处理砂岩SHPB 试验的动态应力应变响应中观察到两种经典力学类型（即I 类和II 类）。通过扫描电子显微镜（SEM），确定了 I 类和 II 类行为中加载后微裂缝特征的微差异。在 I 类行为中，晶间裂纹 (IE) 是通过 SHPB 加载断裂的试样断裂表面裂纹的主要形式，尽管也可能存在一些晶内裂纹。相比之下，II 类行为源于主要的裂纹类型是晶内裂纹。