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Abstract The creep strain from the creep tests under triaxial cyclic loading was separated into the viscoelastic and the viscoplastic strain and the rheological models were established accordingly to describe the variation of creep in the attenuation and steady stages. To describe the accelerated creep stage，a damage factor was introduced into the viscoplastic rheological model. As a result，a modified viscos-elastic-plastic creep model was established. The sensitivity of parameters of the model was analyzed. The creep experiment under triaxial cyclic loading on coal with various deviatoric stress levels was carried out and the elastic and plastic strains of coal were analyzed separately. Comparisons between the results obtained from creep model and creep tests showed that the proposed model described the overall rheological deformation of coal under cycle unloading path.
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Received: 09 May 2014
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2015, Vol. 34 
