Innovative methods of ground improvement for two problematic UK railway earthwork materials

The paper focuses on emerging (bio-) chemical techniques used to improve engineering properties of two problematic earthwork materials of the UK rail network to address transport earthwork infrastructure resilience in view of climate change. Studied techniques include novel cementing agents (e.g. alkali-activated cements), and/or soil cementation through calcite precipitation mediated by screened and isolated non-pathogenic indigenous bacteria, enhanced by bioaugmentation and electrokinetic treatment. The proposed treatments were evaluated based on unconfined compressive strength (UCS). For the ash, regular cement gave the best results however the feasibility of using alternative stabilisers merits further study. UCS and CaCO3 measurements proved biocementation of peat for a number of treatment combinations. Electrokinetic treatment enhanced the strength of the peat. Ongoing work is carried out to optimise treatments and implementation methods towards the upscaling of the techniques.