Samenvatting

This research study aims to determine the most suitable soil stabilization method for ensuring a stable and sustainable foundation for the design of a railway embankment expansion between Zoeterwoude East and Hazerswoude-Rijndijk. The research question is addressed through a comprehensive analysis using both qualitative and quantitative methods.
The importance of this research lies in the need for a reliable and durable foundation for the railway embankment expansion, considering factors such as stability (examined using D-Geo Stability), sustainability, costs, risks, and maintenance. By identifying the most effective soil stabilization method, the study aims to contribute to the design and construction practices in the field of railway infrastructure.
To answer the research question, a systematic approach is adopted, including a Multi-Criteria Analysis (MCA) as the quantitative method. The MCA involves evaluating different criteria and considering three selected variants: the conventional pile mattress, method of preloading, and geotextile encased columns. The qualitative methods involve assessing assumptions, limitations, and available data to inform the analysis.
The result of the MCA indicates that the geotextile encased columns emerge as the most suitable soil stabilization method based on the evaluated criteria. These columns demonstrate high stability and sustainability. While the method has not yet been used for the stabilization of railway embankments in the Netherlands, the long-term cost-effectiveness and low maintenance requirements makes them a preferred choice.
In conclusion, the research establishes that implementing geotextile encased columns would ensure a stable and sustainable foundation for the railway embankment expansion. The study highlights the limitations, assumptions, and areas for further research, such as the inclusion of rolling stock characteristics, (critical) train speed effects, subsidence from peat oxidation, and obtaining more comprehensive and accurate data.
Recommendations for follow-up research include conducting field studies to collect accurate data, monitoring the long-term performance of geotextile encased columns, assessing economic feasibility in more detail, investigating the environmental impact, and exploring emerging soil stabilization methods. These recommendations aim to enhance knowledge, improve design practices, and contribute to the development of sustainable and resilient railway infrastructure.
Overall, this research provides valuable insights into soil stabilization methods for railway embankments, offering a foundation for informed decision-making and promoting the long-term stability and sustainability of railway infrastructure.