LAUSR

The Poynting-Thomson creep model is one of the classical combined creep models; however, it fails to demonstrate the plastic creep and the accelerated creep stage, which limit the popularization and the use of the model. The New Poynting-Thomson (NP-T) creep model is established to enhance the existing Poynting-Thomson creep model by the damage theory and the viscoplastic unit in this paper. On the basis of deducing its constitutive equation in three-dimensional finite difference form, The NP-T creep model is secondarily developed by using Visual C ++ language and FLAC3D built-in FISH language. The results of a parameter inversion indicate the superiority of the NP-T creep model that can be applied in non-uniform stress field. After validating its accuracy by the FLAC3D software, the NP-T creep model is used in a numerical simulation to reflect that the roadway stability is gradually weakened with the increase of the surrounding soft rock thickness.