Bao Xiankai, Huang Shunjia, Lv Yongjun, Huang Yue, Wang Lizhi, Zhang Xiaofan
School of Civil Engineering, Inner Mongolia University of Science and Technology, 014010, Baotou, Inner Mongolia, China.
Inner Mongolia Autonomous Region Building Structure Disaster Prevention and Mitigation Engineering Technology Research Center, Inner Mongolia University of Science and Technology, 014010, Baotou, Inner Mongolia, China.
Sci Rep. 2025 Apr 7;15(1):11898. doi: 10.1038/s41598-025-90733-6.
During the tunneling process in high-temperature environments, the surrounding rock mass is subjected to periodic pressurization and depressurization, making it prone to instability and failure. To investigate the damage and failure of high-temperature rock under cyclic loading-unloading, uniaxial cyclic loading-unloading tests and ABAQUS numerical simulations were conducted on granite samples at 30 ℃, 40 ℃, 55 ℃, 75 ℃, and 100 ℃. The acoustic emission characteristics and Kaiser effect of the granite were studied, along with the changes in mechanical properties and damage failure characteristics under cyclic loading-unloading. The results indicate that: (1) Under cyclic loading-unloading, the peak strength of granite initially decreases and then increases as temperature rises, Notably the minimum peak strength and maximum area of the hysteresis loop are observed at 75 ℃. (2) Under different temperature conditions, the Felicity ratio of granite increases with the number of loading cycles and eventually converging towards a value of 1. However, the rate of increase gradually diminishes progressively, and the Kaiser effect becomes increasingly pronounced. (3) Further numerical simulation studies were conducted on granite at 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, and 100 ℃. The identification of Kaiser points through the analysis of fractured unit volume is consistent with the cumulative acoustic emission ringing count methodology, Furthermore, the Felicity ratio of granite exhibits a negative correlation with the extent of damage. (4) As the temperature and the number of cycles increase, the damage variable of granite initially increases before subsequently declining, with its maximum observed at 80 ℃. The results indicate potential risks of structural failure in high-temperature granite subjected to cyclic loading-unloading, thereby offering valuable insights for engineering construction.
在高温环境下的巷道掘进过程中，围岩受到周期性的加压和减压作用，使其易于失稳和破坏。为了研究高温岩石在循环加卸载作用下的损伤与破坏情况，对30℃、40℃、55℃、75℃和100℃的花岗岩试样进行了单轴循环加卸载试验及ABAQUS数值模拟。研究了花岗岩的声发射特性和凯泽效应，以及循环加卸载作用下力学性能和损伤破坏特性的变化。结果表明：(1)在循环加卸载作用下，花岗岩的峰值强度随温度升高先降低后升高，值得注意的是，在75℃时观察到最小峰值强度和最大滞回环面积。(2)在不同温度条件下，花岗岩的费利西蒂比随加载循环次数的增加而增大，最终趋于1。然而，其增大速率逐渐减小，凯泽效应越来越明显。(3)对50℃、60℃、70℃、80℃、90℃和100℃的花岗岩进行了进一步的数值模拟研究。通过分析破裂单元体积来识别凯泽点与累积声发射振铃计数方法一致，此外，花岗岩的费利西蒂比与损伤程度呈负相关。(4)随着温度和循环次数的增加，花岗岩的损伤变量先增大后减小，在80℃时达到最大值。结果表明，高温花岗岩在循环加卸载作用下存在结构破坏的潜在风险，从而为工程建设提供了有价值的见解。
