Deformation and strength characteristics of geogrid-reinforced soil retaining wall under change of loading rate and its FEM simulation

The deformation and strength characteristics of geogrid-reinforced soil retaining wall are investigated based on the results from physical model tests performed under change of loading rate. The model is vertically loaded with a rigid strip footing placed on the crest of the backfill. The vertical settlement rate of the footing is changed step by step several times and a set of creep loading and cyclic loading stages are performed during change of loading rate. The obvious rate-dependent behaviors of geogrid-reinforced soil retaining wall are observed. Namely, on a step-change in the loading rate, the footing pressure-settlement relation is changed correspondingly. It is due to the viscous properties of the backfill (sand) and the reinforcement (geogrid) and the interactions between them. On the basis of dynamic relaxation method, the nonlinear finite element method (FEM) analysis technique is developed to simulate the above physical model tests. In the FEM analyses, the unified three-component elasto-viscoplastic constitutive model is used to describe both sand and geogrid. It is shown that the aforementioned FEM can well simulate the deformation and strength behaviors of geogrid-reinforced soil retaining wall under change of loading rate.