Comparison of Ground Improvement Techniques - Comparison of Different Techniques Based on Technical, Environmental and Economic Aspects

Abstract

This master’s thesis compares three ground improvement techniques: deep mixing, stone columns, and lightweight fill. The methods are designed to achieve comparable settlement levels and are evaluated for two case studies with clay soils in western Sweden, representing different soil depths and conditions. In addition to settlement performance, the impact on slope stability is analysed. Furthermore, the environmental impact and cost of the techniques are assessed and compared. The results indicate that deep mixing is generally the most effective technique in terms of set tlement reduction and slope stability improvement relative to cost. However, it also exhibits by far the highest environmental impact among the studied methods. Lightweight fill, on the other hand, generally results in the lowest environmental impact and represents a competitive alternative, particularly in deep soil conditions where column-based methods would otherwise require floating solutions. Stone columns are most suitable for sites with thinner clay layers and favourable ground conditions, and they have the additional advantage of significantly reducing the consolidation time. Overall, the findings show that the optimal ground improvement technique is highly dependent on site specific conditions, as well as the relative importance of technical performance, cost, and environmental impact.