Long-term lateral displacement of geosynthetic-reinforced soil segmental retaining walls

Abstract

The service limit-state design of Geosynthetic-Reinforced Soil (GRS) retaining walls requires accurate estimation of the lateral facing displacement at the end of construction as well as after years of creep. However, before a simplistic but rational methodology for this purpose can be developed, mechanisms governing the short-term and long-term lateral facing displacements must be clarified. In this study, extensive Finite Element analyses were carried out using a calibrated Finite Element procedure to investigate and attempt to better understand the lateral facing displacements of segmental GRS walls at the end of construction and after 10 years of creep under constant gravity loading. The study found that among the two main components of lateral facing displacement, the deformation of reinforced soil zone was largely governed by reinforcement spacing and reinforcement stiffness, while the influence of reinforcement length was negligible. Soil stiffness also played an important role in the lateral deformation if large reinforcement stiffness and/or small reinforcement spacing were used. In contrast, reinforcement length to a very large extent determined the lateral displacement at the back of reinforced soil zone. With constant reinforcement length, the reinforced soil zone could be treated as a deep beam. The displacement at the back of reinforced soil zone was then determined by the earth pressure, beam depth, and beam stiffness, the last of which is a function of soil stiffness, reinforcement spacing, reinforcement stiffness, and facing stiffness. The study found that isochrone stiffness can be used to interpret the lateral deformation of GRS walls under working stress condition.