Optimization of Geofoam Shape for Earth Pressure Reduction on Debris Flow Barriers

A debris flow barrier is a structure used to prevent erosion caused by debris flow, and is typically installed in countries with mountainous areas, such as Korea. However, owing to earth pressure, several debris flow barriers become damaged. Geofoam is a reinforcement material widely used in the design of debris flow barriers, not only in dams/retaining walls but also in bridges and landscaping. The purpose of this study was to examine the lateral earth pressure reduction effect of geofoam on debris flow barriers, and to find an optimized geofoam shape that satisfies specific conditions. In this study, the debris flow barrier, backfill, geofoam, and foundation were modeled using ABAQUS, a two-dimensional finite element method program. Models A-C were simulated and compared at backfill lengths of 10, 20, and 40 m. The debris flow barrier model was used at a mountain slope of 25 degrees. To determine the geofoam shape and analyze the stability coefficients for sliding and overturning, ten diverse scenarios were considered. According to the results, Scenario 10, with a reversed triangle shape of geofoam, was the most effective in all cases, which reduces the earth pressure significantly. In the case of Model C, a reversed triangle geofoam reinforcement reduces the lateral earth pressure on the backside of the structure by an average of 34.43%.