Study on load-bearing behavior and failure analysis of GRS abutments with gabion facing

To evaluate the load-carrying behavior and failure mechanisms of geosynthetic-reinforced soil (GRS) bridge abutments with gabion facing, four large-scale model tests were conducted under localized vertical loading. Different reinforcement spacings and geogrids were adopted as experimental variables. Beam seat settlement, lateral facing displacement, additional vertical stress, and reinforcement tensile strain were continuously measured, and the failure modes were also analyzed based on post-loading observations. The results revealed that, reducing reinforcement spacing significantly increased the ultimate bearing capacity and reduced both settlement and facing deformation. The two geogrids with different grid configurations and rib arrangements exhibited different deformation responses under higher loading conditions. Furthermore, the measured additional vertical stress and reinforcement strain distributions indicated that localized vertical loads mainly affected the upper to mid-upper portion of the abutment, where stress concentration and reinforcement mobilization were most pronounced. The observed failure mode was characterized by progressive relative movement between the reinforcement and gabion facing, followed by excessive lateral facing deformation and eventually toppling of the upper facing. These findings provide insights into the load transfer and failure mechanisms of gabion-faced GRS abutments employing frictional reinforcement-facing connections and offer useful references for engineering design.