Improving Containment Dike Stability with Geosynthetics: A Study on Louisiana Coastal Soils

The stability of containment dikes is vital to Louisiana’s coastal restoration, particularly for marsh creation projects addressing rapid wetland loss. This study evaluates the geotechnical behavior of native dike soil from CPRA Project BS-0032, reinforced with geosynthetics to improve shear strength under applied loading. Large-scale (305 mm × 305 mm) direct shear tests were conducted on soil specimens with varied dry densities and moisture contents. Geotextile and geogrid reinforcements were placed horizontally at the interface between the upper and lower shear boxes, simulating single-interface shearing conditions typical of reinforcement pullout behavior. The primary research goal was to quantify the effect of reinforcement on interface peak shear strength, interface friction angle, and cohesion. Results indicate that geosynthetic inclusion enhances interface strength, with improvements influenced by both soil properties and reinforcement type. These findings inform the optimized design of geosynthetic-reinforced containment dikes, promoting more stable and resilient infrastructure in Louisiana’s dynamic coastal environment.