Abstract:A life-cycle sustainability assessment evaluated and compared the impacts of five ground improvement methods commonly implemented to mitigate liquefaction: compaction grouting, deep dynamic compaction, deep soil mixing, vibro compaction, and vibro replacement (i.e., stone columns). Using typical scopes of work provided by geotechnical contractors who specialize in ground improvement, this study developed sustainability benchmarks for the life-cycle impacts and costs of each method, quantified the consequences of the risk and uncertainty inherent in ground improvement projects, and examined impacts to land and soil resources that occur throughout the life cycle. Results showed that deep soil mixing and compaction grouting are the most impactful and costly methods due to the use of portland cement, an energy- and emissions-intensive material. Vibratory methods and deep dynamic compaction are more sustainable, despite the fact that their impacts and costs are more variable and uncertain. Although many factors influence ground improvement design selection (e.g., safety, performance criteria, feasibility, and cost), the results of this study may help inform decision making to realize more sustainable infrastructure.

Key words: geotechnical engineering, soil improvement, liquefaction mitigation, sustainability, life-cycle assessment, LCA, LCSA