Creep Test of Hard Rock and Modified Generalized Kelvin Creep Model

Abstract

By a circular increment step load and unload method, a set of rheological experiments were performed to study the creep properties of amphibolite and the deformation data of instantaneous elasticity, instantaneous plasticity, viscoplasticity and viscoelasticity could be obtained. The results showed that: the creep threshold of amphibolite(σs1) was 25.46MPa; whenσs1s2, the proportion of plastic deformation in the total deformation was very small and the value of creep deformation always tended to a stable value; whenσ>σs2, the rock samples failed rapidly and had no obvious creep. According to the creep and failure properties of amphibolite, the generalized Kelvin creep model was acted in series with the Mohr-Coulomb criterion and a modified generalized Kelvin creep model was built and the corresponding visco-elasto-plastic constitutive relationships were deduced. The modified model could simulate visco-elasto-plastic deviatoric behavior and elasto-plastic volumetric behavior. The model parameters of amphibolite were fitted according to the data of rheological test. The testing curves were coincident well with the theoretic curves by comparison which showed the creep properties and the plastic flow of hard rock could be well simulated by the generalized Kelvin creep model.

Study on the Creep of Damage-Containing Anthracite: Theory and Experiment

“…Liu et al [30] analyzed the creep law of deeply saturated rocks and proposed the Schofield-Scott-Blair model based on joint rheology. Wan et al [31] investigated the creep properties of amphiboles using the cyclic incremental-step-loading method. They combined the generalized Kelvin creep model with the Mohr-Coulomb criterion to derive the corresponding viscous-elastic-plastic transient relationship.…”

Creep Behavior of Intact Loess Followed Unloading Paths

“…Furthermore, some researchers have also constructed creep models based on empirical, yielding surfaces, and damage effects (Sivasithamparam et al, 2015;Chang et al, 2020). For loess, creep models have been proposed, based on the results of triaxial creep tests and theoretical analysis (Li et al, 2011), and there are four creep models, including Cam-Clay model, Duncan-Chang model, Kelvin model, and Burgers model (Graham et al, 2001;Liu and Carter, 2002;Nguyen et al, 2011;Wan et al, 2011). Among these creep models, the Burgers model is widely used to describe the creep behavior of various rocks and soils due to its intuitive concept, clear parameters and physical implications, and simple calculations.…”