Large-scale model tests of geosynthetic-reinforced soil bridge abutments under various hydrological conditions and traffic loads

Geosynthetic-reinforced soil (GRS) bridge abutments provide significant advantages, including low carbon emissions, cost-effectiveness, and efficient mitigation of vehicle bumping at the bridge end. This study evaluates the performance of GRS bridge abutments under varying hydrological conditions and traffic loads, based on three sets of large-scale model tests. The study examined three distinct working conditions: natural drying, unsaturation due to rainfall, and full saturation due to groundwater. Key parameters such as vertical settlement, horizontal displacement, vertical acceleration, earth pressure, pore water pressure, and geogrid load were monitored, compared, and analysed. The results demonstrate that GRS bridge abutments perform effectively across different hydrological conditions, with deformation remaining below critical thresholds under normal design loads. Heavy rainfall, even at an intensity of 200 mm/h, has a minimal impact on the stability of GRS bridge abutments when open-graded coarse sand backfill is used, due to its excellent drainage capacity. However, under fully saturated conditions, stability is significantly compromised, with increased deformation and pore water pressure. These findings emphasise the need for proper drainage and design to ensure the long-term stability of GRS bridge abutments.