Proper estimation of reinforcement loads is a key to evaluate the internal stabilities of Geosynthetic- Reinforced Soil (GRS) structures. Prediction methods for reinforcement loads within GRS structures in current practice can be categorized into two approaches: force equilibrium approach (i.e., earth pressure method and limit equilibrium method) and deformation based approach (i.e., K-stiffness method and finite element method). Until today, the effects of these methods have not been extensively examined and compared yet. In this paper, the reinforcement loads measured from two full-scale and carefully instrumented GRS walls are used to examine the prediction of reinforcement loads by the aforementioned methods. These walls are 3.6m high with different facing stiffness; one wall was constructed with a stiffer segmental modular block face and the other with a flexible wrapped-around face. Comparison results from both wall cases indicate the force equilibrium approach overly predict the reinforcement loads. The K-stiffness method shows an obvious underestimate under surcharging conditions. The finite element predictions are sufficiently accurate under working stress conditions but do not successfully predict the measured reinforcement loads under large loading conditions. Furthermore, a stiff facing in a reinforced soil wall can restrain wall deformation and thus result in significant reductions in reinforcement loads compared to the flexible facing system. However, the influence of facing stiffness is typically not accounted for in the force equilibrium approach, so that the force equilibrium approach significantly overestimates reinforcement loads for the stiff face wall. Reasons of discrepancy between predicted reinforcement loads and measured data are discussed. The results obtained from this study provide insightful information for the design of GRS structures.
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