Seismic deformation evolution of rigid facing reinforced soil retaining walls for high-speed railways

One shaking table model test with a uniform-length geogrid layout was reproduced numerically for validation, followed by FLAC 3D analyses of 14 full-scale cases with uniform-length and stepped layouts. The test showed a rotation-dominated facing response and migration of the largest monitored settlement from the near-facing region toward the geogrid-end region. Numerical results revealed three deformation stages, from near-facing localization through propagation into the reinforced backfill to middle-geogrid-dominated deformation, accompanied by downward migration of the geogrid high-strain zone. Geogrid length had little influence on maximum settlement at 0.05–0.20 g. At 0.30–0.60 g, settlement became concentrated near the geogrid terminations, and differences among geogrid-length cases became pronounced. At 0.50 g, increasing geogrid length from 0.60 H to 1.50 H , where H denotes the wall height, reduced maximum facing displacement and maximum settlement by 14.5% and 42.2%, respectively. Stepped layouts redistributed settlement between the short- and long-geogrid termination regions, producing single- or multi-peak profiles. With maximum surface settlement as the primary criterion, no stepped layout showed a clear advantage at 0.10 g. At 0.30 and 0.50 g, SL-3, comprising three upper 0.60 H -long layers and 22 lower 1.00 H -long layers, produced the lowest maximum settlements among the stepped layouts investigated.