吴秋红,夏宇浩,赵延林,等. 不同温度及冷却速率下花岗岩动态拉伸力学特性[J]. 煤炭学报,2023,48(5):2179−2193. doi: 10.13225/j.cnki.jccs.2023.0127
引用本文: 吴秋红,夏宇浩,赵延林,等. 不同温度及冷却速率下花岗岩动态拉伸力学特性[J]. 煤炭学报,2023,48(5):2179−2193. doi: 10.13225/j.cnki.jccs.2023.0127
WU Qiuhong,XIA Yuhao,ZHAO Yanlin,et al. Effects of high temperature and cooling rate on dynamic tensile mechanical properties of granite[J]. Journal of China Coal Society,2023,48(5):2179−2193. doi: 10.13225/j.cnki.jccs.2023.0127
Citation: WU Qiuhong,XIA Yuhao,ZHAO Yanlin,et al. Effects of high temperature and cooling rate on dynamic tensile mechanical properties of granite[J]. Journal of China Coal Society,2023,48(5):2179−2193. doi: 10.13225/j.cnki.jccs.2023.0127

不同温度及冷却速率下花岗岩动态拉伸力学特性

Effects of high temperature and cooling rate on dynamic tensile mechanical properties of granite

  • 摘要: 深部高温岩石往往会受不同冷媒介质作用,其力学特性的劣化极易诱发岩体工程灾害。考虑3种冷却方式(高温炉中冷却、空气自然冷却及水中快速冷却),首先研究高温(200~800 ℃)花岗岩圆盘试样热−冷处理后其内部微裂纹分布及纵波波速变化规律。然后基于改进的SHPB试验系统,对不同热−冷处理后的花岗岩试样开展动态劈裂试验,研究不同加载速率下试样应力平衡状态、动态拉伸强度及变形破坏特性的演变规律。结果表明:① 岩石内部损伤程度随冷却速率增大而增大,水中冷却后试样波速下降率最大,内部产生的微裂纹数量最多。② 不同温度及冷却速率下试样动态拉伸强度与加载率呈指数正相关关系;200 ℃时,冷却方式对试样动态拉伸强度影响较小;而400~700 ℃时,温度及冷却方式对试样动态拉伸强度影响较大,拉伸强度随温度及冷却速率的增大而降低。③ 温度及冷却方式对试样最先起裂位置处拉伸应变、起裂时间影响较大,最先起裂位置处拉伸应变随温度及冷却速率的增加而增加,起裂时间随温度及冷却速率的增加而缩短。④ 试样主要存在2种破坏模式:I类为试样存在中心主裂纹及端部粉碎区;II类破坏模式复杂,除了存在中心主裂纹及端部粉碎区外,还存在其他方向贯通裂纹。研究结果可为深部高温岩石工程的稳定性控制提供理论参考。

     

    Abstract: Deep high-temperature rock is often subjected to different cooling mediums, and the deterioration of its mechanical properties is easy to induce some rock mass engineering disasters. Based on the three cooling ways, cooled in an oven, cooled in air and cooled in water, firstly, the variations in the P-wave velocity and microscopic cracks of high temperature (200−800 ℃)granite after exposure to heating and cooling treatments were studied. Then, based on the modified SHPB test system, the dynamic tests were conducted by using the disc granite after exposure to heating and cooling treatments, and the stress equilibrium, dynamic tensile strength and deformation and failure of samples were investigated. The results show that the damage degree in the sample increased with the increase of cooling rate, and the water-cooled samples exhibit the largest decrease in P-wave velocity and the largest amounts of newly-generated cracks. The relationship between the dynamic tensile strength and loading rate can be well-fitted using an exponential positive correlation. The cooling rate has less influence on the dynamic tensile strength when the sample reaches 200 ℃. When the sample reaches 400−700 ℃, the temperature and cooling rate have great effects on the dynamic tensile strength, and the dynamic tensile strength decreases with the increase in temperature and cooling rate. The temperature and cooling rate have great influences on the dynamic tensile strain and fracture initiation time of the sample at the initiation position. The dynamic tensile strain increases with the increase in temperature and cooling rate, and the fracture initiation time decreases with the increase in temperature and cooling rate. There are two failure types for samples with different heating/cooling treatments. Type I is the central main crack and the crushed zone at loading ends in the sample. Type II is very complex, there are central main crack, crushed zone at loading ends and cracks in other directions. The present results will be much helpful for providing the theoretical reference for the stability control of deep high-temperature rock engineering.

     

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