Field Instrumentation and Evaluation of Modular-Block MSE Walls with Secondary Geogrid Layers

AbstractMechanically stabilized earth (MSE) walls reinforced with geosynthetic have been used extensively in highway projects around the world. Typical vertical spacing of geosynthetic reinforcement used in the design of an MSE wall is 0.6 m. This large reinforcement spacing requires a high reinforcement connection strength and may result in wall-facing bulging in the practice. To alleviate such problems, use of secondary reinforcement between primary reinforcement layers was proposed. However, this idea was not verified in the field. In this study, three MSE wall sections reinforced with geogrid layers were constructed and monitored in the field: (1) an MSE wall section with uniaxial geogrid layers as primary and secondary reinforcement; (2) an MSE wall section with uniaxial geogrid layers as primary reinforcement and with biaxial geogrid layers as secondary reinforcement; and (3) an MSE wall section with uniaxial geogrid layers as primary reinforcement only (i.e., the control section). Earth pressure ce...