GEOTECHNICAL APPROACH TO EMBANKMENT MAINTENANCE

This article discusses some remedial measures for stabilising railway embankments. The choice of the most appropriate and economical solution depends on the severity of the problem, the nature of the soil, the performance specification, and, most important, the access constraints. Several geotechnical and geostructural approaches are outlined. Lime stabilisation is used relatively little in the UK; lime is introduced principally to hydrate and strengthen clay. Soil nailing is a method of reinforcing soil slopes, that redistributes the weight of the soil mass as it settles, by putting the nails into tension. It is used extensively in the UK, and provides economical solutions for motorway widening, new embankment construction, and railway cuttings. Specialist grouting can be used to stabilise ash-filled embankments, provide new support for railway tracks, and prevent settlement, for example from pipe jacking. One of the best approaches to embankment stabilisation is the use of minipiles to provide a structural soil retention system. By installing the piles from the top of the embankment, as close as possible to the railway tracks, it minimises the potential for soil movement. A case study of the adoption of this solution is presented, for the strenghtening of clay embankments on a railway line in North London.