Statistical damage model for dry and saturated rock under uniaxial loading based on infrared radiation for possible stress prediction

Rock fracture is the root cause of collapses of the overburden and mine water inrush. Monitoring and identifying the precursor information of the mine surrounding rock during the progressive failure process are the foundation for an advancement of mine safety. In this paper, the infrared radiation observation experiments of both dry and water saturated sandstone under uniaxial loading was carried out. The representative dry and water saturated sandstone samples with specific microstructure and composition, mechanical, and infrared radiation characteristics during the fracture process were studied. The results show that water saturation not only weakens the mechanical properties of rock, but also promotes infrared radiation which can be used as a precursor for stresses. The saturated rock uniaxial compressive strength, elastic modulus, compaction stress decreased and the magnitude of Infrared Radiation Variance (IRV) increased: which are 0.55, 0.54, 0.67 and 10.69 times that of the dry rock, respectively. Furthermore, water saturation changes the failure mode of rock from tensile failure to tensile shear composite failure. In addition, an innovative constitutive model of rock under uniaxial loading based on infrared radiation is established. The model considers the compaction stage and integrates the advantages of the lognormal distribution and Weibull distribution. The established piecewise constitutive model gives the coefficient of performance of more than 0.95, therefore, this model can be effectively used for the prediction of stress in both dry and saturated rocks. The research results can lay a theoretical and experimental foundation for monitoring the stability of engineering rock masses using infrared radiation.