Experimental and numerical analysis of wrapped geogrid-stabilized high-fill embankment: Seismic response and composite reinforcement mechanisms

This study investigated the seismic response and reinforcement mechanism of high-fill embankment reinforced with geogrid and pile-slab structure through shaking table tests and numerical method. Experimental results demonstrated that the geogrid-reinforced composite embankment can still maintain structural integrity under high-intensity seismic loading (PGA ≥0.8g), exhibiting only surface cracking and localized soil extrusion. The acceleration amplification factor (AAF) exhibited both “elevation effect” and “surface tendency effect”, while strain distribution in the pile-slab structure followed characteristic arch-shaped and M-shaped patterns. Geogrid reinforcement effectively constrained soil deformation and redistributed stresses, delaying the development of pile bending moment and embankment displacement. Its reinforcement efficiency increased with seismic intensity. Validated numerical models reproduced shear strain localization-induced cracking at both embankment surfaces and embankment-accumulation interfaces. Shear strain propagation exhibited a progressive inward expansion from the embankment surface under seismic excitation. Parametric studies further revealed that reducing geogrid spacing can improve constraint effects, minimize displacement, and mitigate internal shear deformation. These findings underscore the synergistic role of geogrids and pile-slab structures in redistributing seismic thrust forces, offering critical insights for optimizing reinforcement strategies in seismically active regions.