REINFORCED SOIL allowed an embankment to be built on soft compressible ground in a recent Glasgow project, as an alternative to removing large volumes of alluvium and building a traditional embankment.
The scheme incorporated a load transfer platform, and the use of reinforced soil reduced the embankment's footprint and thus piling costs.
Main contractor Morrison Construction had to build an access road over a rail line for client Crowwood Grange's housing development at the former Cardowan Colliery at Stepps in Glasgow.
Ground conditions adjacent to the rail line were soft alluvial deposits including peat to depths of about 6m. Embankments up to 10m in height were needed to connect to a new bridge being constructed over the railway.
The original scheme, developed by the client's design engineer Babtie, involved excavation and replacement of the soft alluvial deposits and construction of traditional embankments with 1 in 2 side slopes above.
However Morrison Construction was looking to reduce construction costs and increase buildability, says the company's project manager David McWhirter.
It developed an alternative bid with Keller Comtec, which involved a piled embankment with a Tensar geosynthetic reinforced load transfer platform above. Use of steep reinforced soil embankments reduced the embankment footprints, and thus the number of driven cast insitu piles needed in the load transfer platform. Comtec's contract involved the design, supply and construction of the load transfer platform and reinforced soil embankments.