摘要： The failure of surrounding strata in the excavation faces is the root cause of some disasters, including roof caving, coal pillar instability, and water inrushes, during the extraction of coal resource. Identifying the abnormal phenomena and precursor information before rock failure forms an important theoretical foundations of achieving safety operation in coal mines. The infrared radiation (IR) on the surface of rock will change during loading process (Luong 1990; Freund et al. 2007; Gong 2013). By monitoring the IR, the deformation and failure characteristics of rock can be obtained (Sheinin and Blokhin 2012; Mineo and Pappalardo 2016; Sun et al. 2017; Fiorucci et al. 2018), reliable information for predicting rock failure precursors may be obtained, as well (Wu et al. 2015; Salami et al. 2017). In addition, the water content affects the IR characteristics during the failure of rock (Liu et al. 2010). To quantitatively characterize the IR from the rock surface during loading process, Wu (1998) first proposed the index of average infrared radiation temperature (AIRT). Later, Liu et al. (2015), Yang et al. (2017) and Ma et al. (2016) proposed new indexes for quantitative analysis, e.g., variance, entropy, characteristic roughness, euclidean distance, and VDIIT. The previous experimental results revealed that these new indexes could be used to explain a lot of IR phenomena during rock failure (Pappalardo 2017; Zhang et al. 2018). For example, the author have investigated the inherent relation between stress and IR during rock loading (Ma et al. 2017), and found that stress had significant, universal, and hysteretic control effects on IR. However, there are still difficulties during the acquisition of IR mutation data and the estimation of mutation amplitude under loading conditions. Therefore, new appropriate indexes should be proposed for more accurate determination of the quantitative relation between stress and IR. To further investigate the relation between stress and IR, two mutation coefficients, stress rate (SR) and variance of differential infrared image temperature (VDIIT), were adopted in this study. The related IR observation experiments were conducted using samples with different water content, so as to obtain the quantitative relation between stress and IR under uniaxial loading tests.