Numerical Study of the Influence of the Interaction Distance, the Polymeric Strips Pre-Tensioning, and the Soil–Polymeric Interaction on the Performance of Back-to-Back Reinforced Soil Walls

Abstract

This study describes the results of a series of 2D finite element method (FEM) numerical models of 6 m high back-to-back reinforced soil walls using the geotechnical software PLAXIS. These structures are used to support embankments, especially for bridge abutment approaches. The quantitative influence of problem geometry, strip pre-tensioning, strip type, and surcharging on horizontal displacements, development of soil shear and plastic zones, lateral earth pressure, and reinforcement loads is presented. The numerical results demonstrate that the back-to-back reinforced soil walls perform jointly when the distance of interaction between the two opposite walls is greater than the interaction distance, which is defined in FHWA, and is contrary to the results of the FHWA design guideline. The walls of the two opposing sides interact with each other when they are close enough and with an overlapping reinforcement layout. Pre-tensioning load can contribute to achieving vertical wall-facing alignment at the end of construction. Using perforated/holed strips, the tensile loads at the end of construction were reduced by about 30% due to the improved polymeric–soil interface strength and stiffness.