Abstract: Based on analyzing the mechanisms of the pavement diseases in the cut-and-fill embankment, the working mechanism of the geogrid reinforcement is analyzed. A series of field tests are carried out to investigate the vertical displacements of the pavement, the vertical earth pressures in the embankment fill and the tensile forces of the geogrid. In addition, a numerical model is established for simulations according to the dimensions of the embankment in situ. Through the numerical simulations, the tensile forces and the vertical displacements are observed after the period of construction of the embankment. The tensile forces and the displacements of the embankment are studied, in condition, different vertical loads act on the pavement, and the geogrid with different elongation stiffnesses is spread. The results show that, the geogrid used for cut-and-fill embankment treatment can alleviate the differential settlement of the cut-and-fill embankment. The vertical earth pressures are almost equal to the weight of the overlying embankment fill. The reinforcement of the geogrid has an effective length, the tensile forces and displacements of the geogrid layers are greater at the junction of the cutting and filling areas; the settlement of the upmost geogrid is the smoothest, while the tensile force of the geogrid at the bottom of the embankment increases sharply at the junction. Vertical loads have limited influences on the tensile forces and the displacments of the geogrid layers; and the influences are gradually reduced with the increase of buried depth of the geogrid. The settlements of the geogrid layers increase slowly with the increase of the vertical loads on the pavement; and the geogrid layers at the junction area have the greatest tensile forces. With the increase of elongation stiffness of the geogrid, the tensile forces of the geogrid increase obviously, while the displacement changes very negligible.

Key words: cut-and-fill embankment, geogrid, field test, numerical simulation, tensile force, displacement