The Brazilian disc specimen (BDS) and flattened Brazilian disc specimen (FBDS) test was conducted on the thermally damaged rock (from room temperature to 1000°C) that was subjected to static loads. The temperature effects on the splitting tensile strength (STS) of BDS and FBDS were investigated. Then, the FBDS test was conducted in thermally damaged rock by way of the split Hopkinson pressure bar. The high-temperature and strain rate effects on STS were evaluated, and the relationship between the STS growth factor and the high-temperature and strain rate was established. The results indicated that in the sandstone failure modes, not only did a strain rate threshold exist but also a temperature influence threshold existed. Below 800°C, the FBDS under a high strain rate failed through the plane that was determined by the diameter perpendicular to the two platforms. The sample failure mode took the form of two complete halves. Increasing the loading rate resulted in a triangle-like crushing area being observed at both platform ends; the higher the loading rate was, the larger the crushing area. When the treatment temperature exceeded 800°C, the sample failure mode took the shape of being crushed.

中文翻译：

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热损伤岩石的劈裂拉伸力学行为与破坏特征

在承受静载荷的热损伤岩石（从室温到1000°C）上进行了巴西圆盘样品（BDS）和压扁的巴西圆盘样品（FBDS）测试。研究了温度对BDS和FBDS的劈裂抗张强度（STS）的影响。然后，通过分裂的霍普金森压力棒在热损坏的岩石中进行FBDS测试。评估了高温和应变速率对STS的影响，并建立了STS生长因子与高温和应变速率之间的关系。结果表明，在砂岩破坏模式中，不仅存在应变率阈值，而且还存在温度影响阈值。低于800°C，FBDS在高应变率下无法通过由垂直于两个平台的直径确定的平面。样本失败模式采用两个完整的一半的形式。加载速率的增加导致在平台的两端都观察到三角形的破碎区域。加载速率越高，破碎面积越大。当处理温度超过800℃时，样品破坏模式呈压碎的形状。