Paper: Mobilization of Reinforcement Tension within Geosynthetic-Reinforced Soil Structures

From Kuo-Hsin Yang, Jorge G. Zornberg and Richard J. Bathurst: This paper examines the mobilization of reinforcement tension within geosynthetic-reinforced soil (GRS) structures at working stress and at large soil strains. Fully-mobilized reinforcement tension is assumed in most current design methods for the internal stability of GRS structures. In these methods the mobilized reinforcement tensile load is assumed to be equal to mobilized horizontal soil forces
computed using active earth pressure theory. However, comparison with reinforcement tension loads measured in the field has shown that this approach is conservative (excessively safe) by as much as a factor of two. This observation has prompted the current study in which stress data obtained from a numerical study and two instrumented large-scale GRS retaining walls were used to examine the relationship between mobilized reinforcement tensile load and mobilized soil shear strength. The results show that the ratio of reinforcement tensile load and mobilized soil shear strength is not constant Only when the average mobilized soil shear strength exceeds 95%, is reinforcement tensile capacity mobilized significantly. Nevertheless, less than 30% of reinforcement strength is mobilized when the average mobilized soil shear strength reaches peak soil shear capacity. These results help explain why current design methods lead to computed reinforcement loads that are very high compared to measured loads under operational conditions.