Soil reinforced retaining wall structures are materiallymore efficientthan competing construction solutions such as gravity and cantilever walls. Nevertheless, the behaviour and interactions between the com ponent materials are com plex and not fully understood. Current design methods are typically limited to simple cases with respect to material properties, geometry, and boundary conditions. Advanced numerical models using finite element and/or finite difference methods offer the possibilityto extend the understanding ofthese systems and to predictwall performance under operational conditions. In this Thesis, numerical models were developed and shown to give satisfactory predictions ofwall behavior when compared with results of instrumented physical structures. The verified models were useful for sensitivity analyses using a range ofwall geometries and boundaryconditions, material parameters and different constitutive models. As examples ofthe obtained results, the compressibility ofthe precast panel bearing pads significantly modified the axial vertical facing load but has no significant effect on the tension developed in the soil reinforcement layers. Also, the stiffness ofthe foundation soil has greater effect on the tension developed in soil steel reinforcing elements than for polymeric reinforcement layers.lt has been possible to perform sensitivity analysis using parameters that define soil-structure interactions. Such interactions have been analyzed using different commercial software programs and bydefining them with elements from the continuum media using 2D and 3D models. Laboratory reinforcement pullout tests using steelladder and polymeric strips were performed as part of the Thesis. Those parameters that have the greatest influence on soil-reinforcement interaction are identified, quantified, and compared to default-design wlues anda range ofvalues used to calibrate numerical models. From the results of2D and 3D numerical models suitable correlations have been obtained to allow 2D models to be used in plane strain reinforced soil walls with discontinuous soil reinforcement elements in the running walllength ofthese structures. With a proper sustainability assessment it has been possible to make quantitative comparisons between reinforced soil wall structures and other alternativés performing the same function (such as gravity and cantilever walls) construcfed to different heights. Using a modelbased on the multi-attributeutilitytheoryand wlue analysis decision-making, the best solutions with least negative impact were identified in an example set of alternative earth retaining wall options from a sustainable perspective. The results include possible scenarios based on the relative importance ofthe three pillars ofsustainability(i.e., environmental, economic, and sociallfunctional) as judged bydifferentstakeholders. Reinforced soil walls turned outto be the best choice in most cases analyzed, based on a quantitative end score. The models and analysis methodologies developed as part ofthis Thesis work have improved understanding ofthe behavior ofthese structures, and offered possibilities to improve and optimize designs in the future.