Environmental impacts of mechanically stabilised earth walls

Mechanically stabilised earth (MSE) walls have gained widespread popularity in North America because of their cost-effectiveness and reliable performance. Although the use of carbon-intensive materials for MSE walls is significantly lower compared to conventional retaining walls like concrete gravity walls and cantilever walls, heavy earthwork and transportation activities are involved in the construction of MSE walls, which increase their carbon footprint. The intensity of construction and transportation activities need particular attention because these are heavily reliant on the combustion of fossil fuels. In this study, the environmental impacts of MSE walls, reinforced by two common types — steel strips and geogrid — are quantified using life cycle assessment (LCA). A parametric study is conducted to investigate the effects of (i) soil properties, (ii) material properties of reinforcement, (iii) applied load, (iv) design parameters, and (v) hauling distances of materials on the global warming impact of MSE walls. Based on the study, reference charts are developed for the purpose of quick estimation of global warming impact of MSE walls based on design dimensions, applied load, and site conditions.