Creep model of rock based on piecewise simulation

In order to achieve a better description of rock creep behaviour, the model creating idea of piecewise simulation of rock creep is proposed on the basis of phase characteristics. The improved Maxwell model, which is composed of an improved soft-matter element based on variable order fractional calculus and a spring element, is used to achieve the simulation of rock steady creep phase. Based on the way of strain trigger, an improved creep body element is used to achieve the simulation of rock unsteady creep phase. Combining the improved Maxwell model and the improved creep body element, a new three-element creep model is proposed. The creep model is verified by using the typical creep curve data of rock salt. The results show that the three-element creep model proposed can be used to perfectly simulate the three phases of rock salt creep, and the idea of piecewise simulation is reliable.