The Gedling Access Road is a new 3.8km single carriageway road to the North East of Nottingham city centre, linking the B684 Mapperley Plains Road at the North Western end of the scheme to the A612 Trent Valley Road / Nottingham Road to the South Eastern side of the site. Running parallel with the A6211 Arnold Lane and through the centre of the old Gedling colliery site, the road serves the new £140m Chase Farm housing estate redevelopment.
Working on behalf of Nottinghamshire County Council and key project partners Gedling Borough Council, Keepmoat Homes, Homes England and D2N2, consultant Via East Midlands Ltd managed the design and delivery of the scheme. Balfour Beatty were awarded the construction contract with preparatory ground works undertaken by contractor Mick George, including the construction of a substantial 1km long section of steep embankment (1:2 slope) to raise the road to connect to the existing Plains Road. Planners required as small a construction footprint as possible and the steep embankment maximises the re-use of fill materials from the cut. This prevented the need to deposit unconsolidated fill elsewhere along the route and avoids the carbon intensive transfer of fill offsite. The mercia mudstone is stable at 1:2 and the challenge was to retain a minimum of 200mm topsoil onto the compacted slope, up to 45m long in places.
ABG were consulted to recommend a design to prevent erosion of the new 1:2 gradient embankment. The solution also needed to assist traction for the back actor and dozer equipment working in the clay based soils during wet weather. ABG Erosaweb geocell, manufactured by ABG, was proposed to contain the topsoil onto the compacted steep slope, enabling a natural grass finish to establish once completed, and providing a light-weight and low carbon alternative to using a wire mesh.
ABG Erosaweb geocell GWX 200/300 for soil retention on steep slopes
The ABG Erosaweb cells retain the topsoil fill whilst still allowing water to drain through. The large 4m x 6m GWX 200/300 panels have a cell size of 200mm deep x 300mm diameter and are simply stretched out into position down the slope before pinning into place.
Expanding ABG Erosaweb panels into position & pinning
The avoidance of importing crushed stone for the embankment reduces the scheme’s environmental impact and fits in with the overall programme of ecology mitigation measures, including the planting of 5.84 hectares of new trees, a 40% increase in woodland area.
The ABG Service
In total 20,000 m2 of ABG Erosaweb GWX 200/300 was supplied. Supporting calculations were completed for the veneer stability and for the loading of specific machines used to complete the backfilling operations. Assistance was provided at the beginning and during the completion of the works to assist with setting out and establishing the correct pinning pattern.
ABG Erosaweb veneer stability and pinning pattern calculations
Drone video showing vegetation establishing onto Erosaweb