| Project name: | Blackpool Commercial Park |
| Location: | Cork, Eire |
| Keller company: | Keller Comtec |
| Client: | PJ Hegarty |
| Techniques used: | Reinforced soil |
| Project duration: | 5 weeks carried out in Autumn 2003 |
Keller’s use of the Textomur reinforced soil system to reroute a river channel around the perimeter of a new commercial park in Cork, is the first time the technique has been used in Southern Ireland.
Keller’s 300m-long reinforced soil embankment wall at the new Blackpool Commercial Park development in Cork, provides an engineered channel for the re-routed River Lee which once flowed straight through the middle of the site.
It is the first use of Textomur reinforced soil, which makes use of angled steel profiles as formwork for the front face, in Southern Ireland.
The wall is up to 4.5m high and has been designed to provide scour protection and give a green landscaped finish to the new river channel.
It is built up in 600mm lifts, with horizontal soil reinforcement provided by a geogrid. The front face is formed with the 70 degree inclined steel profiles and a lightweight, inner geotextile facing layer to hold the topsoil in place.
The technique avoids the 'bag of sausages' appearance that you eventually get with many wraparound reinforced soil techniques, which is particularly important for the wall in Cork, which has been designed with curves to create a natural looking river channel.
Fill material, is compacted in behind the wall, although the front 300mm is topsoil loosely packed in by hand to create a reliable growing medium.
Although there is a plentiful supply of imported high grade fill material in Cork, a general benefit of the technique is that a wide range of fill materials can be used – in many cases site-won fill will be acceptable -reducing the need to import or export materials from site.
Before Keller arrived on site, main contractor Hegarty had already formed a rough new channel along the boundary of the site. Keller is forming the curved reinforced soil structure while protected from the river by a thin earth bund that will be removed once the wall is in place.
For sections of the wall below river level, the topsoil is replaced with stone at the front face in order to protect from scouring.
The wall is also be used to support the foundations of a small footbridge across the new river. Here galvanised steel cages are used with the front face brought to vertical onto which a rubble wall will be attached to maintain a natural look.
Ultimately the non-galvanised steel grid facing is sacrificial, but during the work, it doubles as a safety barrier. A particular benefit of the Textomur system, compared with a more conventional retaining structure, is that it requires fewer skilled operatives. It is really a simple earthworks application – and does not need a heavily engineered foundation. Good progress can be made without the expense of employing skilled wet trades.
In Cork, Keller expects to complete its curved 300m-long, 4.5m high wall with just a supervisor and two men, in just five weeks.
