Construction of the Murrayfield Stadium station on the new Edinburgh Tram scheme reached a milestone earlier this month with completion of ground improvement work by Keller Foundations.
Working for main contractor Graham, which working on behalf of Bilfinger, Keller constructed more than 700 wet soil mix columns to provide support for a new embankment approach to the Waters of Leith Bridge at the station by the stadium. The 1.5m diameter columns were installed to depth of between 3m and 4m to strengthen the made ground at the site, which overlays glacial drift.
According to Keller, the variable made ground and the need to squeeze the tram line between the stadium and an existing rail line made the soil mixing technique ideal. The company said that it drew on its experience of using the approach for US clients to deliver this soil mixed solution using a specially adapted bored piling rig with counter-rotating mixing blade to mix the soil and cement slurry.