To study the granular soil’s rheological properties, a large triaxial rheological apparatus was developed by assemblying a axial pressure and confining pressure providing equipments for the SZ30-4 large scale triaxial apparatus, and the stability examinations proved that the stability of this pressure providing equipments was competent for granular soil’s rheological tests. The large triaxial rheological apparatus have the axial pressure ranging from 0 to 1.0 MPa, confining pressure of 50kPa, 100kPa, 150kPa, 200kPa, 250kPa and the soil sample dimension of Φ=300mm, h=600mm. A series of granular soil creep tests were executed on this apparatus. The tests discussion shows that stress conditions are the main factors, which affects the creep properties of granular soil. There are different rheological properties at different stress level. eg. at low stress level (S=0.1) for the elastic, at middling stress level (0.2
0.8) for the non-linear viscous plastic. The total rheological strain nonlinearly increase with stress level increments but linearly increase with confining pressure increments. According to the discussion of redstone granular soil’s creep properties, a rheological component based on hyperbola function was presented, and a nonlinear viscous elastioplastic rheological constitutive model was set up by putting the component and the Burgers model in series. The creep properties analysis shows the rheological model can describe the granular soil’s whole rheological phase well.