Developing a two-step improved damage creep constitutive model based on soft rock saturation-loss cycle triaxial creep test

Abstract

The study of the time-dependent deformation behavior of soft rock under water–rock interaction is of great significance to reveal slope creep deformation behavior. In this study, the saturation-loss cycle's triaxial creep test was performed, and the creep deformation, creep rate, and long-term strength of silty mudstone were analyzed. A two-step improved modeling method was also proposed. Firstly, by introducing fractional Abel viscous pot and aging factor, a one-dimensional creep constitutive model was established based on the Burgers model. And then the three-dimensional creep damage constitutive was derived through Laplace transform. Finally, the Levenberg–Marquardt (L–M) algorithm method was used to identify the creep curve and calibrate the model parameters. The new constitutive model could reflect the soft rock's creep characteristics during saturation-loss cycle.