An extended Nishihara model for the description of three stages of sandstone creep

Abstract

Many gently dipping translational rock slides have taken place in red Jurassic strata in Wanzhou which is located in the middle bank area of the Three Gorges Reservoir, China. In order to study the mechanism of these translational rock slides, conventional triaxial tests and creep tests on sandstone specimens from red Jurassic strata in Wanzhou are performed, and the rheological properties of the sandstone at accelerating creep stage are discussed. The quasi-static Nishihara model for transient and steady-state creep is modified by adding a strain-triggered inertial element in series, resulting in a phase of quadratic accelerating creep. The model fits the experimental data at all stages of creep, allowing its parameters to be inferred from the data. Finally, a sensitivity study for the analytical solution of the proposed model is carried out, showing the effects of the inertial element and stress level on the creep strain of sandstone.