Seismic performance of geosynthetic-reinforced earth retaining walls subjected to strong ground motions

Abstract

There is general evidence that the good performance of geosynthetic-reinforced earth retaining walls (GRWs) observed after strong seismic events can be attributed to their capacity to redistribute seismic-induced deformations within the reinforced zone, provided that the reinforcements are characterised by adequate extensional ductility. Therefore, it is desirable to promote the activation of internal (or local) plastic mechanisms, involving the reinforcement strength, since the design phase. In this study, the seismic performance of two earth retaining walls is compared. Specifically, a pseudo-static approach is adopted to conceive a GRW with a seismic resistance, expressed by the critical seismic coefficient kc, that involves activation of an internal plastic mechanisms, and a conventional retaining wall, in which the same critical seismic coefficient kc is attained for an external (or global) plastic mechanism. Finite difference dynamic analyses are carried out to evaluate the seismic performance of the two walls. In the analyses, a real acceleration time history is applied at the base of the models. The results of the dynamic analyses show that, compared to the wall in which external plastic mechanisms develop, the wall designed to activate internal plastic mechanisms exhibits a better seismic performance, with lower permanent displacements computed at the end of the seismic event.