Tiered geosynthetic-reinforced soil (GRS) walls in transportation engineering are often applied in high-retaining soil structures and are typically subjected to traffic cyclic loading. However, there has been limited research on the dynamic performance of tiered GRS walls. Three reduced-scale model walls were conducted to investigate the dynamic performances of two-tiered GRS walls with different strip footing locations (d/H) under cyclic loading. The test results demonstrated that cyclic loading parameters such as average load P0 and load amplitude PA have a significant effect on the dynamic performance of the tiered walls. However, the change in loading frequency f has a minor effect on the settlement and lateral deformation when the GRS wall reaches a relatively stable state. Under the same P0 and PA, the measured maximum additional vertical stress Delta sigma v,max decreases with the increase of frequency f, whereas minimum additional vertical stress Delta sigma v,min increases. The stress distribution profile along the horizontal direction at the lower-tier wall crest is related to the strip footing location. The bearing capacity of the GRS wall increases and then decreases with increasing d/H within the reinforced zone of the upper-tier wall. The variation magnitude and distribution profile of the lateral deformations are influenced by the d/H and cyclic loading levels, especially for the upper-tier wall. When the strip footing remains in the reinforced zone of the upper-tier wall, potential slip surfaces go deeper as it moves away from the wall face. Finally, a power relationship between the calculated factor of safety and the maximum lateral deformation monitored from model tests for the two-tiered GRS walls under cyclic loading is established.
