DEM Analysis of Stresses and Deformations of Geogrid-Reinforced Embankments over Piles

The geosynthetic-reinforced pile-supported embankment is one of the favorable ground improvement techniques used in the construction of earth structures over a compressible soil when limited construction time is available and limited deformation is permissible. Various methods are available for the design of the geosynthetic-reinforced platform based on various load transfer mechanisms from the embankment to the piles and the compressible soil. The existence of the geosynthetic layer makes the mechanisms more complex. This study focuses on the behavior of geogrid-reinforced embankments over piles compared with the behavior of unreinforced embankments. The numerical simulations of the unreinforced and reinforced pile-supported embankments were conducted using the discrete element method (DEM). The embankment fill was simulated using unbonded graded aggregates of diameters ranging from 9.2 to 20.8 mm and the geogrid was simulated using bonded particles. This study investigated the changes of vertical and horizontal stresses and porosities, the vertical displacements within the embankment fill, and the deflection and tension in the geogrid. The simulation results showed that the coefficient of lateral earth pressure in the embankment fill changed from an initial at rest condition to a passive condition at certain locations after the compression of the compressible soil. The embankment fill dilated during the development of soil arching. The embankment load was transferred to the piles owing to the reorientation of the principal stresses. The results also showed that the geogrid reinforcement significantly reduced the total and differential settlements at the top of the embankment. (c) 2012 American Society of Civil Engineers.