Numerical Simulation of Mechanically Stabilized Earth Walls under Surcharge Loading: Fid-Bau Portal

Numerical Simulation of Mechanically Stabilized Earth Walls under Surcharge Loading

Ambauen, S.J. / Leshchinsky, Ben

A numerical model, simulating the complex behavior of reinforced soil walls using the finite element method, was developed to evaluate the behavior of a surcharged, geosynthetic-reinforced retaining wall with modular block facing. A nonlinear elastic-plastic constitutive soil material model was calibrated to experimental plane strain test data, while the performance of the wall model was validated against full-scale laboratory testing of an identical geosynthetic-reinforced wall. The results from both the constitutive model and the wall model were also compared to predictions made in the literature. It was found that the behavior of the reinforced soil wall was adequately represented by the numerical model at the end of construction and throughout the surcharge loading sequence. Furthermore, a parametric analysis demonstrated that use of dense reinforcements could reduce service state deformations at the wall face. The numerical model developed through this study was shown to be able to accurately simulate the response of geosynthetic-reinforced soil walls under surcharge loading. Laboratory material test results were used to calibrate the backfill soil constitutive model, and full-scale instrumented wall experimental data were used to validate the numerical wall model's response through the staged construction with lift compaction, and through the application of a uniform surcharge load to the wall crest. Along with previous work by Pichler et al. (2012), the numerical model, developed using the ABAQUS FEM platform, demonstrates the capacity of this software to model and examine the complex behavior of composite soil retention structures now specifically with variable reinforcement spacing and surcharge placements. Additional data awaiting investigation include the generated lateral earth pressures against the facing, relative vertical settlements, strain levels in the reinforcements, and stress dissipation through the soil mass. This study indicated the considerable effect that reinforcement vertical spacing has on serviceability. While further surcharge setback leads to less surcharge influence on wall deformations, increased reinforcement densities enables the wall to be loaded closer to the facing, allowing for shorter bridge deck span lengths and reduced bridge construction costs.