A new rock creep model based on variable-order fractional derivatives and continuum damage mechanics

The creep model is the main form of rock model used to describe the rheological behavior of rocks. A large number of creep models have been proposed, but many are complicated and/or are not able to fully simulate the three stages of rock creep. Hence, an important focus of research on rock creep has been to develop a model with few parameters and better simulation performance. To achieve this, in this study, we propose a new four-element creep model, based on variable-order fractional derivatives and continuum damage mechanics. The newly proposed creep model agrees well with experimental data for Changshan rock salt. The results show that the segmentation treatment is an effective approach for simulating the creep behavior of rocks.