Visco-elastic-plastic model of deep underground rock affected by temperature and humidity

As the depth of exploitation increases, studies on constitutive models of rock affected by temperature and humidity become very important. Based on the Nishihara model, a visco-elastic-plastic rock model was established by using the coefficients of thermal and humidity expansion, thermal viscosity attenuation, humid viscosity attenuation and acceleration rheology components. We used the definition of a controlled heat circle to explain the model. The results show that the behavior of rock, affected by temperature and humidity, is stable as a function of time when the stress is lower than the first yield stress σS1; the creep rate will increase due to the effect of temperature and humidity when the stress is greater than or equal to σS1; the creep rate will accelerate at an increasing rate when the stress is greater than or equal to the second yield stress σS2, which results in a failure of the roadway. The model derived in this study can completely describe visco-elastic-plastic characteristics and reflects the three stages of rock creep.