Table 4 Comparison of the proposed model with existing creep models.
Model | Ability to describe accelerated creep stage | Consideration of water-induced damage | Physical interpretability of parameters |
|---|---|---|---|
Proposed model | Yes, via a nonlinear damage viscous-plastic element. | Yes, implicitly reflected by the variation of identified parameters (e.g., lower E, lower η) under saturated state. | Yes, all parameters (E1, E2, η1, η2, η3, σ∞) have clear physical meanings. |
Improved Nishihara model [14] | No, cannot describe the accelerated creep stage. | No, the model itself does not incorporate a damage variable; water effect is analyzed separately. | Yes, parameters are physically interpretable. |
Expansion creep damage model [16] | Yes, through a damage variable related to hydration expansion. | Yes, explicitly incorporates a hydration-damage variable. | Moderate, the introduction of expansion and damage variables increases complexity. |
SBN-Burgers model [17] | Yes, achieved by the combination of nonlinear elements. | No, the model is developed for saturated rock but does not include a separate damage variable for water. | Weak, some parameters are empirical and lack direct physical meaning. |
