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Use of Secondary Reinforcement to Minimize Lateral Deformation of Geosynthetic-Reinforced Retaining Walls: Numerical Analysis

Field monitoring has demonstrated that secondary reinforcement could reduce the maximum deformation of geosynthetic-reinforced retaining (GRR) walls. However, the effect of secondary reinforcement on the reduction of lateral deformations of GRR walls has not been well studied yet. This study used a finite difference method incorporated in the Fast Lagrangian Analysis of Continua (FLAC) software to develop two-dimensional (2D) numerical models and assess the effect of secondary reinforcement on the reduction of lateral deformations of GRR walls. These models used an advanced soil constitutive model based on the theory of hardening plasticity, called the Cap-Yield (CY) model, to simulate the behavior of backfill. The numerical model was first calibrated and verified against the measured results from a full-scale field test. A parametric study was conducted to investigate the effects of four factors related to secondary reinforcement including secondary reinforcement length, secondary reinforcement stiffness, secondary reinforcement connection, and secondary reinforcement layout. The numerical results show an increase in secondary reinforcement length and stiffness can reduce the lateral deformations of GRR walls. The mechanical connection of secondary reinforcement can also reduce the wall facing deflection. In addition, the wall with a special layout (i.e., fewer but longer secondary reinforcement layers at certain elevations) had relatively smaller wall facing deflections. The results of this study will reduce the lateral deformation of GRR walls with less use of geosynthetics and benefit the geosynthetics community by providing an economical and practical solution for high GRE walls. Also, an equation to estimate the lateral deformation of GRR walls with secondary reinforcement was proposed. The factors that affect the reduction factor (F) were also discussed.