Abstract: Geocell geosynthetics can effectively reduce the deformation of embankments on soft subgrade and enhance its stability, but there are few researches on critical height of geocell-supported embankments. In this study, the limit equilibrium method was employed, and circular sliding failure mode presented in the foundation under the embankment load was assumed firstly. Geocell and its filled soil were regarded as composite material considering its vertical stress dispersion effects and lateral confinement effects. An analytical model about critical height of the embankments was then proposed and its results were compared with that of the finite difference model which was calculated using FLAC. Finally, the effects of geocell height, angle of stress dispersion and friction coefficient between geocell layer and foundation on the critical height of embankments were discussed based on the analytical model. It turned out that the results between theoretical analysis and numerical calculation were well coincident with each other. The critical height of geocell-reinforced embankments was obviously greater than the critical height of unreinforced ones. Increasing the three influencing factors can improve its critical height, and strengthening the lateral confinement of geocell layer was more in favor of the stability of embankments than improving the geocell height and angle of stress dispersion.

Key words: reinforced embankments, geocell, composite material, stability, critical height