摘要 为探究不同层理方向岩石变形破坏过程中的红外异常,开展了单轴压缩下片麻岩红外辐射试验,结合应力、平均温度、方差、温度场分异速率、热像图多种指标研究了破裂过程红外辐射温度的演化特征。结果表明:不同层理片麻岩加载过程红外辐射温度场的演化特征具有相似的阶段性和变化趋势。发现平均红外辐射温度和应力二者之间有较强的线性关系,相关系数均在0.90以上;水平层理试件辐射温度升温速度高于竖直层理试件。方差曲线随应力变化可分为3个阶段,压密及弹性阶段较小且变化平缓,破坏阶段发生大幅度陡升;加载中期和后期出现的异常特征点可作为岩石失稳的前兆信息。对方差求导获取温度场分异速率,定义其第1次偏移0值的点和临破坏偏移0值的点为一、二级预警信号;得出时间预警优于应力预警,且竖直层理试件能达到损伤最低值。红外图像经过多步骤算法降噪处理,图像质量明显增强;前期热像表面呈均匀缓慢变化,中期随应力增加逐渐升温,临近破坏时,热像在破裂位置出现高温辐射异常,其他区域出现低温异常,这种分异现象是岩石失稳的重要红外前兆特征。 Infrared radiation tests of gneiss under uniaxial compression were performed to explore the infrared anomalies in the process of rock deformation and failure in different bedding directions.The evolution characteristics of infrared radiation temperature during the failure process were studied by evaluating factors including stress,average temperature,variance,differentiation rate of temperature field,and thermal image.The results showed that the evolution characteristics of the infrared radiation temperature field in different bedding gneiss loading processes have similar stages and changing trends.The linear fitting of average infrared radiation temperature and stress has a strong linear relationship.The temperature rise rate of the horizontal bedding specimen is higher than that of the vertical bedding specimen.The variance curve with stress can be divided into three stages.The compaction and elastic stage are small and change gently,and a greatly steep rise occurs during the failure stage.The abnormal characteristic points appearing in the middle and later stages of loading can be used as a precursor of rock instability.The variance is derived to obtain the temperature field differentiation rate.The point at which the temperature field differentiation rate shifts to the value of 0 for the first time and the point at which the value of offset to the value of imminent failure shifts to 0 are defined as the first and second warning signals,and it is concluded that time warning is better than stress warning.The infrared image is processed through a multi-step algorithm to reduce noise.The image quality is significantly enhanced.Near the macro-failure,the infrared thermal image has high-temperature radiation anomalies at the fracture position and low-temperature anomalies in other areas.This thermal image differentiation is an important infrared precursor characteristic of rock instability.
出处 《采矿与岩层控制工程学报》 北大核心 2021年第1期92-99,共8页 Journal of Mining and Strata Control Engineering
基金 国家自然科学基金资助项目(51134005) 河北省高等学校科学技术研究资助项目(QN2020125)。
关键词 红外辐射温度 温度场分异速率 方差 前兆特征 红外热像 infrared radiation temperature differentiation rate of temperature field variance precursory characteristics infrared thermal image
