This paper studies the dynamic mechanical characteristics of siliceous sandstone (SS) after elevated temperature treatment and discusses the damage mechanism of structure thermal stress on rock. Firstly, the dynamic compression tests of SS under room temperature (25 °C) and different high temperatures (200, 400, 600, and 800 °C) were carried out using the split Hopkinson pressure bar (SHPB). The rock dynamic curves of stress-strain were obtained, and the variation of the strength, peak strain, and dynamic elastic modulus with strain rate and temperature were discussed. Secondly, the scanning electron microscope (SEM) technique was adopted to determine the change of the rock micro-structure as temperature increases, and the mechanism of thermal damage was analyzed. The results show that the SS is sensitive to temperature, and 200 °C and 600 °C are distinct turning points of mechanical properties. At room temperature to 200 °C, the strength increases slightly, decreases from 200 to 600 °C, and then decreases rapidly; the peak strain decreases first and then increases; the strain rate effect of the dynamic elastic modulus of rock at different temperatures is not obvious, indicating that the rock dynamic elastic modulus is a material property, independent of loading rate. The SEM photographs of rock surface after high temperature show that the internal structure of rock affected by temperature is obvious. Significant changes appear at 400 °C, inconsistent with the inflection point of mechanical properties.

中文翻译：

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温度对硅质砂岩动态压缩行为的影响

研究了高温处理后硅质砂岩（SS）的动态力学特性，并探讨了结构热应力对岩石的破坏机理。首先，使用分开的霍普金森压力棒（SHPB）在室温（25°C）和不同的高温（200、400、600和800°C）下对不锈钢进行动态压缩试验。得到了岩石的应力-应变动力学曲线，并讨论了强度，峰值应变和动弹性模量随应变率和温度的变化。其次，采用扫描电子显微镜（SEM）技术确定岩石的微观结构随温度升高的变化，并分析了热损伤的机理。结果表明，不锈钢对温度敏感，200°C和600°C是机械性能的明显转折点。在室温至200°C时，强度略有增加，从200降低至600°C，然后迅速降低。峰值应变先减小然后增大；岩石动弹性模量在不同温度下的应变率效应不明显，表明岩石动弹性模量是一种材料性质，与加载速率无关。高温后岩石表面的SEM照片表明，岩石的内部结构受温度影响明显。显着变化出现在400°C，与机械性能的拐点不一致。然后迅速下降；峰值应变先减小然后增大；岩石动弹性模量在不同温度下的应变率效应不明显，表明岩石动弹性模量是一种材料性质，与加载速率无关。高温后岩石表面的SEM照片表明，岩石的内部结构受温度影响明显。显着变化出现在400°C，与机械性能的拐点不一致。然后迅速下降；峰值应变先减小然后增大；岩石动弹性模量在不同温度下的应变率效应不明显，表明岩石动弹性模量是一种材料性质，与加载速率无关。高温后岩石表面的SEM照片表明，岩石的内部结构受温度影响明显。显着变化出现在400°C，与机械性能的拐点不一致。高温后岩石表面的SEM照片表明，岩石的内部结构受温度影响明显。显着变化出现在400°C，与机械性能的拐点不一致。高温后岩石表面的SEM照片表明，岩石的内部结构受温度影响明显。显着变化出现在400°C，与机械性能的拐点不一致。