3D Finite Element Analysis of Geosynthetic-Reinforced and Pile-Supported Widening of Embankment over Soft Soil

To minimize the differential deformation between the widening subgrade and the existing one, geosynthetic-reinforced and pile-supported (GRPS) embankment was chosen as a typical geotechnical composite system in Shanghai A11 expressway-widening engineering. Due to the complexity of this problem, 3D finite element analysis was conducted to investigate the mechanical behavior and effect of GRPS embankment in subgrade-widening engineering over soft soil. Analysis results indicate that, GRPS embankment can reduce differential settlement and enhance the stability significantly, spacing of outer piles can be larger than that of the inner piles, and the installation of piles under the existing embankment slope combined with excavation of old filling is very necessary when the height of embankment is not less than 3 meters.