Comparative evaluation of the environmental impacts of geosynthetic Mechanically Stabilized Earth walls

Abstract

Integrating sustainable approaches in all the engineering fields became mandatory for better life and future. This article explains the comparative advantages of Geosynthetic Mechanically Stabilized Earth (MSE) walls over four other conventional types (Plain Concrete Gravity walls; Reinforced Concrete Cantilever walls; Masonry Brick walls; and Gabion Limestone Cage walls) from a sustainability perspective over various heights. The study comprises a detailed life cycle assessment (LCA) following the ISO 14040 and 14044 frameworks. The results revealed that constructing MSE walls rather than the other conventional walls contributes to 10 of the 17 United Nations (UN) Sustainable Development Goals (SDGs). GaBi's software and embedded database were utilized for the first time in such an assessment. The article demonstrated that the construction of gravity walls requires large amounts of cement/concrete, which emit a significant amount of geogenic CO2. In contrast, the construction of MSE walls requires considerably less concrete and more backfill. The construction of cantilever walls requires less concrete than gravity, yet more than MSE walls for their construction. The structure of masonry walls was found to have less impact on the environment than the construction of comparable gravity and cantilever walls. The benefits of MSE walls over conventional walls increased with increasing wall height. The significant benefit comes from using soil backfill as the chief structural component rather than concrete. This article is deemed an essential step in achieving circularity and circular economy regarding sustainable earth fill retaining structures.