## 1 Introduction  
The rock creep constitutive model can describe the creep mechanical behavior of rocks under long-term loading [1]. Its main research methods include directly applying empirical fitting formulas to creep test results, component models established through the combination of series and parallel connections of various components and the addition of nonlinear terms. Three kinds of constitutive models of rock are established by using the elastic-plastic theoretical framework, damage mechanics and endochronic theory [2]. The empirical constitutive model of rock rheology is established based on the results of creep experiments using function fitting. Among them, logarithmic and power exponential functions, as well as mixed functions, are the main forms of empirical formulas for rock creep. The existing research results indicate that the rock creep empirical model is simple, intuitive and applicable with high certainty, which is in good agreement with the experimental results [3; 4; 5]. However, it cannot fully reflect the accelerated creep stage. In addition, the empirical model is only an approximation of mathematical formulas, and the physical meaning of the model parameters is not very obvious, so it cannot obtain creep mechanical parameters that can be applied to engineering practice, greatly limiting its development [6; 7]. The rock creep element model includincludedes basic elements such as elasticity, viscosity, and plasticity. Each basic element represents different creep properties of the rock. Integrating the basic components, in series or parallel, which is a composite component model that can reflect various creep characteristics can be obtained. The research on constitutive models of rock elements mainly focuses on the following three aspects: (1) introducing new nonlinear components to establish a new constitutive model of the components, (2) taking the parameters in the model as non-stationary values, and (3) introducing new methods and theories to establish the model [8; 9; 10]. In recent years, more and more experts and scholars have conducted in-depth research on the nonlinear creep mechanical behavior of rocks based on the advantages of component models, and established many new nonlinear constitutive models using methods such as substitution and addition [11; 12]. However, the creep properties exhibited by rocks under complex stress states and geological environments are very complex. In practical engineering, it is not a simple combination of components that can comprehensively describe the constitutive relationship during the creep process of rocks. Therefore, several researchers, based on the fundamental principles of thermodynamics and from the perspective of energy dissipation in the rock creep process, established elastic-plastic constitutive models by defining the plastic yield surface and plastic potential energy equation in the rock creep process to describe the mechanical and deformation behavior in the rock creep process [13; 14]. The study of elastic-plastic constitutive models based on thermodynamics has been widely used on the international scale [15]. By finding suitable yield surface equations and plastic potential energy equations, the establishment of elastic-plastic constitutive models can be achieved [16; 17]. The coupling between plastic flow and damage through the introduction of damage variables is the foundation for in-depth research on the real structural changes in rock interior, which also provides a reasonable approach for studying elastic-plastic damage models [18]. The simulation of the creep behavior of rocks under permeable water pressure is the future trend and direction of the development of elastic-plastic constitutive models [19; 20].