Experimental study of the influence of temperature and cooling method on dynamic mechanical properties and damage of granite
Experimental study of the influence of temperature and cooling method on dynamic mechanical properties and damage of granite
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DOI：
10.1002/ese3.1249
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发表时间：
2022-07
影响因子：
3.8
通讯作者：
Yan Xi;Haoyu Wang;Chunqing Zha;Jun Yu Li;B. Guo
中科院分区：
文献类型：
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作者：
Yan Xi;Haoyu Wang;Chunqing Zha;Jun Yu Li;B. Guo
冷却处理后高温岩石力学性能的变化越来越受到关注。然而，只有少数的研究已经进行了动态特性参数。因此，本研究的目的是进行动态损伤分析的高温岩石受到不同的热冲击。因此，将试样分组并加热至200°C、400°C、600°C和800°C，并且通过自然冷却、水冷却和液氮冷却来冷却它们。采用不同的冷却方式，对高温花岗岩试件进行了超声波探测器试验、分离式霍普金森压杆试验和扫描电镜试验。随后计算了动态应力-应变曲线和性能的变化规律，并对破片的形貌和微观形貌进行了比较。在此基础上，对热冲击损伤和冲击损伤演化进行了定量评价。研究结果表明，随着处理温度的升高，岩石的动态峰值应力和弹性模量降低，峰值应变增大，急冷对岩石动态特性的影响更为显著。而且，当损伤因子大于0.51时，动应力应变的变化加快，导致结构在冲击荷载作用下失稳。研究成果有望为地热资源的开发利用和地下工程应用提供充分的理论依据。
The change in mechanical properties of high‐temperature rock after cooling treatments is getting increasing attention. However, only a few studies have been conducted on the dynamic characteristic parameters. Therefore, this study aims to perform a dynamic damage analysis of high‐temperature rocks subjected to different thermal shocks. Accordingly, the specimens were grouped and heated to 200°C, 400°C, 600°C, and 800°C, and they were cooled by natural, water, and liquid nitrogen cooling. Ultrasonic detector tests, the split Hopkinson pressure bar experiments, and scanning electron microscope tests of the high‐temperature granite specimens were conducted using different cooling methods. Subsequently, the change rules of dynamic stress–strain curves and properties were calculated, and the morphology and micromorphology of fragments were compared. Based on the outcomes, the thermal shock damage and impact damage evolution were evaluated and quantified. The findings revealed that when the treatment temperature increases, the dynamic peak stress and elastic modulus decrease, while the peak strain increases, and the effect of rapid cooling was more significant in the influence of rock dynamic characteristics. Moreover, when the damage factor is more than 0.51, the change of dynamic stress‐strain is accelerated, leading to the instability of the structure under the impact load. The research results are expected to provide an adequate theoretical basis for the development and utilization of geothermal resources and underground engineering applications.