FEM Analyses on Creep Characteristics and Strain Fields of Geogrid-Reinforced Sand

Both sand and polymer geogrid reinforcement are known to exhibit more-or-less complicated stress-strain-time or load-strain-time behavior including instantaneous non-linearity and viscous effects. Creep is one of the most important time-dependent behaviors of material, which is an inherent response of the viscous property of material. Due to interactions between the viscous sand and reinforcement, the creep characteristics of geogrid-reinforced sand could be very complicated. A nonlinear finite element method (FEM) analysis technique incorporating the unified three-component elasto-viscoplastic constitutive model for both sand and geogrid was developed. The FEM can simulate the whole process including the constant strain rate loadings and the creep loading stages. In addition, the development of strain fields during the creep loading can also be reproduced by the FEM simulation. By comparing the simulated results with the experimental results, it was shown that the proposed elasto-viscoplastic FEM could well simulate the creep characteristics of geogrid-reinforced sand, especially for the high stiffness following a creep loading stage.