Seismic performance of GRS walls with gabion fascia vis-à-vis segmental block fascia retaining walls

Abstract

Geosynthetic-reinforced soil (GRS) walls are widely used in seismic regions due to their flexibility, cost-effectiveness, and favorable deformation characteristics. However, the influence of fascia type on their seismic response is not yet fully understood. This study presents a comprehensive numerical investigation of the seismic behaviour of GRS walls with segmental block and gabion fascia systems using finite element modelling. To isolate the effect of fascia type, both wall configurations are designed with identical geometry, backfill properties, reinforcement layout, and construction sequence. The GRS wall response is evaluated under static using gravity load and dynamic loading conditions using the 1995 Kobe earthquake motion as input. The analyses focus on mobilized reinforcement and connection loads, acceleration amplification along the wall height, lateral earth pressure distribution, and the development of potential failure surfaces. A realistic field construction scenario is simulated through staged construction, including the application of transient compaction loads, and results are assessed at the end-of-construction (EOC) condition. The results indicate that reinforcement and connection loads increase toward the lower portion of the wall due to combined overburden and seismic effects, with gabion fascia walls consistently mobilizing lower loads than segmental block walls. Acceleration amplification is higher near the wall face than within the reinforced zone because of reduced confinement, while gabion fascia walls exhibit slightly higher amplification associated with internal void rearrangement. Lateral earth pressures generally follow a Rankine-type triangular distribution, but segmental block facias develop higher pressures, particularly near the wall base under seismic loading. Failure surfaces inferred from peak reinforcement loads deviate from classical Rankine assumptions, curving toward the face in segmental block walls and developing deeper within the reinforced zone in gabion walls. Overall, the study demonstrates that gabion fascia GRS walls exhibit superior seismic performance compared to segmental block systems and highlights the limitations of conventional Rankine-based assumptions in capturing the actual failure mechanisms of GRS walls under dynamic loading.