Steel faced system
The use of steel meshes (rectangular aperture or hexagonal woven meshes) to form sub vertical and vertical reinforced soil structures. Often with stone facings used behind the mesh facings or, if temporary, lined with geotextile.
Rigid steel meshes can be used to provide both slope surface and soil reinforcement. Lengths of steel mesh, usually of rectangular aperture, can be bent to the required slope angle to form shutters: the inclined section reinforces the slope surface and the horizontal section is directly connected to reinforcing geogrids.
The slope face, in addition to having the steel mesh, can be lined with geomats or other erosion control systems that can be hydroseeded to speed up the growth of the vegetation. Alternatively, for slopes steeper than 60°, rocks can be inserted behind the steel mesh to provide a gabion-like finish. For vegetated slopes, the mesh can be protected against corrosion or left to corrode as a sacrificial element; for gabion-like finishes, corrosion protection (galvanisation and/or coating) is required to ensure longevity of the structure.
Similarly, sheets of hexagonal woven wire mesh can be provided ready to be folded in three parts: a horizontal section, a facing section, that can be kept in place with support brackets and lined with bio- or geomats, and a return horizontal top section. A wrap around system of this type also provides a means of fixing the slope face mesh directly into the retained soil and to any further geo-component used to reinforce it. The woven wire is galvanised and/or coated for corrosion resistance.
A steel mesh retaining system was successfully used as a steep faced retaining solution for a new roundabout approach within the highway scheme for Heathrow Terminal 5. The system was used to provide the required changes in slope profile and to support the establishment of high spec vegetation aided by an irrigation system .
A woven wire mesh system was used to reinforce the 70° slope of an embankment constructed during the widening of the A2/A282 junction in Kent. The steep embankment was required to leave undisturbed an existing hedgerow supporting several nationally scarce and endangered insects; the vegetation was successfully established thanks to the use of biomats and hydroseeding .
- BS EN 14475:2006 Execution of special geotechnical works – reinforced fill
- BS 6031:2009 Code of practice for earthworks
- BS8006-1:2010 Code of practice for reinforced soils and other fills
- DMRB Volume 4 Section 1 Part 4 (HA 68/94) Design methods for the reinforcement of highway slopes by reinforced soil and soil nailing techniques
- TRL Current Topics in Transport CT37.5 Geotextiles in civil engineering – update (2005 – 2008)
