Creep of rock viscoelastic plastic aging damage based on Poyting-Thomson
To accurately describe the nonlinear changes in strain during the rock creep process and the time-dependent damage within rocks under high stress,based on the element model theory and damage mechanics theory,an improved Poyting-Thomson model and Murayama body model were combined in series with a Newto-nian body to construct a viscoelastic-plastic time-dependent damage creep model that can accurately describe the entire process of rock creep.The rationality and applicability of the improved model were verified,and the variation laws of elastic coefficient,viscosity coefficient,and stress were discussed.The results show that the correlation coefficients between the improved model and the creep process experimental data are all greater than 0.96;under the uniaxial stress condition,the elastic coefficient exhibits a nonlinear increase with increas-ing axial pressure,while the viscosity coefficient exhibits a nonlinear decay;under triaxial stress conditions,both the elastic coefficient and viscosity coefficient are affected by confining pressure and axial pressure,exhib-iting nonlinear changes with increasing axial pressure.This indicates that the constructed viscoelastic-plastic time-dependent damage model is fully applicable to the analysis of the uniaxial and triaxial creep processes of rocks.
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维普
