Sustainability assessment of earth-retaining wall structures

Abstract

This paper describes a sustainability assessment methodology and example to select the best sustainable option from candidate conventional gravity and cantilever wall types and steel and polymeric soil-reinforced, mechanically stabilised earth (MSE) walls of different heights. Analyses were carried out using the value integrated model for sustainable evaluations (Mives) methodology, which is based on value theory and multi-attribute assumptions. The paper identifies how indicator issues are scored, weighted and aggregated to generate final numerical scores that allow solution options to be ranked. The final scores include an adjustment based on stakeholder preferences for the relative importance of the three sustainability pillars (environmental, economic and societal/functional). The analysis results show that MSE wall solutions were most often the best option in each category compared to conventional gravity and cantilever wall solutions and, thus, most often they were the final choice when scores from each pillar were aggregated to a final score. However, when cost was weighted most highly of the three pillars, then the conventional wall solutions gave the highest (best) Mives score for walls 3 m high. If environmental issues were the most important concern of stakeholders, then the MSE solutions were the best solution, particularly for walls 5 m high and higher.