Study on Strength Characteristics of Interlayer Rocks Based on Thermal-Mechanical Coupling

For deep resource mining and engineering construction, the mechanical properties of intercalated rock mass are important factors affecting its stability. The influence of temperature on the strength of interlayer rock mass poses a severe challenge to engineering construction. In this paper, the thermal-mechanical coupling calculation model was established by particle flow code (PFC2D), and then to study the uniaxial compression response of interbedded rock masses after the thermal loading. The failure strength, peak strain and microcrack development of the specimen in the uniaxial compression stage are then critically analyzed. The results show that: (1) the large displacement area generated during thermal loading is mainly concentrated on both sides of the interlayer, decreases as the boundary distance ratio increases. In contrast, the peak contact force is less sensitive to the interlayer location. (2) The relationship between the number of microcracks and vertical strain derived from uniaxial compression mainly varied in three stages: the microcrack development stage, the stage of rapid vertical straining, and the stage of gradual development of microcracks with persistent deformation. When T = 400 degrees C, the relationship curve tends to change in two stages: Microcrack growth stage and microcrack development stage with vertical strain increasing. (3) when T = 100, 200 and 300celcius, the failure strength gradually increases as the boundary distance ratio increases. When T = 400celcius, the change of failure strength is small with the increase of boundary distance ratio. Under high-temperature conditions, the failure strength of the sample is less affected by the position of the interlayer.