Abstract: Sand-filled embankment with cover layer is an important embodiment of the green road concept. In order to investigate the ultimate bearing capacity characteristics, failure morphology and reinforcement behavior of sand-filled embankment under load, we designed a model of geogrid-reinforced sand-filled embankment, and modified US GCTS’s USTX-2000 dynamic and static triaxial loading device for loading tests on the model with varied reinforcement layer, reinforcement length, and cover thickness. According to the obtained results of ultimate bearing capacity, normal cumulative deformation and displacement change of the embankment slope and cover layer, we concluded that the geogrid reinforcement could significantly improve the ultimate bearing capacity of the sand-filled embankment and reduce the normal cumulative deformation on the right and middle side of the embankment cover as well as on the top and middle of the slope; so does increasing the cover thickness. The sliding surface of unreinforced embankment was a broken line in the embankment and did not invade the foundation through the slope toe; and the maximum displacement occurred at the boundary between the clay and the sand core at the top of the slope. Geogrid reinforcement and increasing the thickness of the cover layer soil could make the sliding surface and the maximum displacement move towards the interior of the embankment without changing the shape.

Key words: geogrid, sand-filled embankment with cover layer, bearing capacity, reinforcement behavior, cumulative deformation, sliding surface