Comparing the Seismic Responses of Single- and Multi-Tiered Geosynthetic Reinforced Soil Walls

Geosynthetic-reinforced soil retaining walls higher than 20 ft (6 m) are increasingly employed for critical applications. These walls are usually built in tiered configuration. However, the seismic performance of these walls has seldom been investigated. In this study, a calibrated Finite Element procedure was used to compare the seismic performances of single- and multi- tiered GRS walls. Model walls at a total height of 9 m were analyzed, with one set of walls being single tiered and the other set being tri-tiered. The tier off-set was fixed at 1.2 meter, but the influences of reinforcement length and reinforcement spacing were investigated. The model GRS walls were assumed to have modular-block facing back filled with granular soil and the geosynthetic reinforcements were assumed to be HDPE geogrids. It is found from the Finite Element analysis that the seismic performance of multi-tiered walls is better than that of single-tiered walls, and that the improvement increased with a decrease in reinforcement spacing.