Objective In order to establish a creep model able to describe the whole creep process.Methods Firstly the Viscoelasticity of rock was described with fractional order clay pot elements and a damage body based on the Kachanov damage rate formula so as to establishe a creep model with only four elements by connecting a Hooker body.Then the constitutive equation was extended to a three-dimensional stress state,by considering spherical stress and introducing a yield function to accurately determine whether the rock undergoes unstable creep.Final-ly,the model parameters were analyzed by using the least squares method,and the effectiveness of the model was verified by using creep experimental data of red sandstone and sandy mudstone.Results The theoretical curve of the new creep model was in good agreement with the experimental data curve,able to describe the entire process of rock creep and solve the problem of complex models.Conclusion The new creep model is able to solve the problems of the classical models in describing rock creep and has certain refe1rence value for studying rock creep characteristics.
fractional-order clay pot elementsdamagecreep modelyield functionleast square method
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