Creep properties and viscoelastic-plastic-damaged constitutive model of geogrid

By carrying out the creep tests on geogrid, the creep properties under different loading levels are compared and analyzed. The typical creep models of geogrids suggested in previous studies are categorized and their adaptabilities and reliabilities are evaluated. Based on the results, one viscoelastic-plastic-damaged constitutive model of the geogrid is suggested, then the optimization method is used to determine the model parameters, and its reasonableness and validity are proved. Some conclusions have been drawn: the three types of typical creep models are only suited to describe the attenuation mode creep at a low-stress ratio but not the non-attenuation mode creep at a high-stress ratio. The proposed three-parameter viscoelastic model of geogrid can relatively accurately reflect two-stage attenuation creep properties of geogrid at a low stress. The proposed viscoelastic-plastic-damaged model of geogrid considering viscoplastic deformation and damage characteristics can accurately reflect the three-stage non-attenuation mode creep properties of the goegrid at a high-stress ratio.