Displacement Evaluation on an Innovative Composite Reinforced Soil Structure

Abstract

Geosynthetic materials are widely used in civil engineering. Their application and evaluation are currently ongoing to better understand their behavior during design and construction. This study aims to assess the displacement behavior of a specially designed composite reinforced soil structure for innovative slope protection of riverbanks. Three prototypes were constructed for this study, each consisting of geogrid as the primary reinforcement and geotextile as the secondary reinforcement. The gravel drainage configurations included 0%, 50%, and 100%. The gravel used was 1-1/2”–2” sub-rounded gravel, and low plasticity silt (ML type) served as infill material. Horizontal displacement readings for each soil layer were recorded at the end of construction, when fully saturated, and after applying a 55 kPa surcharge load using horizontally installed rods and line gauges. The results indicated that all prototypes had horizontal displacements below the recommended threshold of 4%, consistent with Federal Highway Administration (FHWA) performance criteria and AASHTO design principles. The prototype without gravel drainage showed the lowest average displacement percentage among all. Therefore, the innovative composite-reinforced soil structure can serve as an alternative slope-protection method for riverbanks. It is advisable to design a conservative anchorage system to prevent deviations between initial and final positions, and to explore additional design variables to enhance the performance of this innovative structure.