Ultimate bearing capacity of geosynthetic reinforced soil abutment centrifuge model tests

Five centrifuge models of geosynthetic reinforced soil (GRS) abutments with segmental block facing were loaded in acceleration field under plane strain condition. Influences factors including reinforcement tensile strength, setback and bearing area width were considered and analysed. Results show that the abutment with stronger reinforcement remained stable under the maximum loading capacity. However, abutments with weaker reinforcement showed excessive vertical strain, local deformation or even collapse. The ultimate bearing capacity increased with the lengthening of setback while decreased due to a larger bearing area. The rupture of reinforcements was observed and considered as the cause of the failures. Comparing with the measured ultimate bearing capacity, the values calculated by the semi-empirical formula of design guideline were significantly conservative. The failure surface of failed abutment developed from rear edge of the bearing area to the middle height of the abutment at an angle of nearly 45 degrees+phi/2. The setback and the bearing area width affected the form and position of the failure surface. The difference between the potential failure surface predicted by available methods and the measured failure surfaces has been discussed, and suggestions for the design and ultimate bearing capacity prediction of GRS abutments with segmental block facing were provided.