To study the rheological properties of subgrade compacted soil, three kinds of subgrade compacted soil's traditional direct-shear and consolidation experiments as well as consolidation creep and shear-consolidation coupled creep experiments were carried out respectively by using improving experimental devices. Their basic mechanical properties and creep experimental data were obtained. Using these experimental data, similar Maxwell rheological constitutive model of subgrade compacted soil was set up with three parameters, which was based on fractional calculus theory and Mittag-Leffler functio...