Centrifuge Testing of Segmental Geosynthetic-Reinforced Soil Retaining Walls Subject to Modest Seismic Loading

Geosynthetic-Reinforced Soil (GRS) retaining walls have been proved to exhibit good seismic performance. With the concept of performance-based design, GRS walls shall be designed to meet different levels of performance under different seismic loadings and the "performance" under modest earthquake must therefore be defined. Three model segmental GRS walls at a height of 19.5 cm (prototype height = 7.8 m) were tested using dynamic centrifuge at a centrifugal force of 40g, two of which are subject to an excitation from the 1995 Kobe earthquake with scaled a_max = 0.24g, and one to a 2-Hz sinusoidal excitation of 0.114g with a duration of 13 seconds. Two of the tested walls were identical but subject to different seismic loadings. The experiment results showed that, under modest seismic loading, GRS walls still had non-negligible permanent deformations after the shakings. The results also emphasized the importance of overall acceleration and duration of earthquake. Under modest excitation, acceleration inside GRS walls amplified considerably, indicating that the design of high GRS walls against modest seismic loading may need to consider the change of acceleration with height.