Numerical investigation on the interaction effect of back-to-back MSE walls with different facing conditions

The behavior of back-to-back mechanical stabilized earth (MSE) walls is significantly influenced by the geometry, especially the horizontal distance between the back of the reinforced soil zone of the two MSE walls. In the Federal Highway Administration (FHWA) design guidelines, two cases are considered based on the horizontal distance. However, no justification is provided for this assumption. Therefore, research is needed to investigate the interaction effect of back-to-back MSE walls with different horizontal distances. In addition, the assumption does not provide a clear provision regarding facing conditions. This paper presents a numerical investigation of the interaction effect of the static behavior of back-to-back MSE walls with different facing conditions. A parametric study is conducted to investigate the effect of horizontal distance, soil friction angles, and wall heights on the lateral soil thrust and required tensile strength. Results show that the maximum facing displacement, lateral soil thrust, and required reinforcement tensile force of the back-to-back MSE walls with different facing conditions generally increase nonlinearly with increasing horizontal distance up to a certain critical value. Design recommendations that account for the interaction effect between the back-to-back MSE walls with different facing conditions on external stability and internal stability are provided.