基于欧氏距离的单轴压缩下粉砂岩热图像演化特性研究

为探寻粉砂岩破裂失稳过程红外异常,引入欧氏距离的方法,通过计算粉砂岩试样各相邻时刻欧氏距离,对单轴压缩条件下粉砂岩红外辐射温度场演化特性进行研究,结合熵值、方差两种指标演化趋势验证欧氏距离方法的可用性。结果表明:欧氏距离、熵值法和方差均能较好地刻画粉砂岩红外辐射温度场各个阶段;压密阶段至弹性阶段前期,欧氏距离存在较多大幅度突升值,表征这一时段内试件自身存在的微裂隙被压缩,产生热摩擦效应,欧氏距离与熵值、方差刻画能力相当;弹性阶段后期至塑性阶段,欧氏距离呈较为平稳起伏交替,表征裂隙稳定发育,欧氏距离刻画能力劣于熵值、方差;峰后阶段,欧氏距离出现大幅度突升,且幅度、频率均大于前面的阶段,表征粉砂岩试样即将破裂,欧氏距离刻画能力优于熵值、方差。

Study on Thermal Image Evolution Characteristics of Silt Sandstone under Uniaxial Compression Based on Euclidean Distance

In order to explore the infrared anomaly in the process of siltstone failure, the method of Euclidean distance was introduced. By calculating the Euclidean distance of siltstone samples, the evolution characteristics of siltstone infrared radiation temperature field under uniaxial compression were studied. Entropy and variance are used to verify the availability of Euclidean distance method. The results show that the Euclidean distance, the entropy method and the variance can describe the different stages of the infrared radiation temperature field of siltstone well. From the compaction stage to the early stage of the elastic stage, the Euclidean distance has a large sudden rise value, The Euclidean distance is similar to the entropy value and the variance characterization. In the late stage of elasticity to the plastic stage, the Euclidean distance is relatively smooth and alternated alternately, which indicates that the fracture is stable and stable. And the range and frequency are larger than those in the previous stage, which indicate that the siltstone sample is about to burst, and the Euclidean distance characterization is better than the entropy value ,variance.