Coupled infrared radiation temperature and acoustic monitoring of damage characteristics on saturated red sandstone under uniaxial compression loading

Deep geotechnical engineering construction is influenced by groundwater. To explore the damage evolution mechanism and multi-physical response characteristics of rock with different water content, the infrared thermography and acoustic emission technology were used to monitor the red sandstone under uniaxial compression loading. The acoustic emission cumulative ringing count, damage variables, and infrared radiation temperature field data were synchronously acquired. A systematic analysis of the acoustic and infrared characteristics of water-saturated red sandstone during progressive failure was conducted. Additionally, based on Grubbs criteria, the GIRT and GIRTS indices were introduced to elucidate the temporal and spatial evolution of damage in different water-saturated rock samples. Furthermore, by integrating the acoustic emission damage and the infrared damage index using a random forest model, a comprehensive acoustic-thermal model was established to identify the mechanical response characteristics of water-saturated red sandstone. The R 2 coefficients exceed 0.95 for all samples, indicating high accuracy and reliability of the prediction model. This research uncovers multiple precursory indicators of red sandstone failure under water-rock coupling conditions, providing a foundation for rock stability monitoring and disaster warning through acoustic-infrared fusion technology.