Vertical hard faces system
The use of split faced concrete blocks, gabion or steel mesh faced composite systems to construct ‘walls’, which are defined as being steeper than 70°.
Many wall systems rely on the soil retaining capability of hard and continuous materials such as concrete (precast panels or sprayed on site), steel meshes and/or crushed stone. The soil face cannot be left exposed due to the steepness of the slope hence the hard surfaces provide for erosion control at the same time as retaining the soil mass.
Typical systems include modular walls with concrete panel facings, gabions and steel mesh es retaining crushed stone or used as support for sprayed concrete. Sprayed concrete can also be applied as a hard finish to soil nail reinforcement of steep slopes.
For aesthetic reasons vertical hard faces wall are integrated with the surroundings by choosing specific finishes for the concrete (which can be textured or coloured) or local stones that can be placed as a cladding on gabion faces. Vegetation of walls is sometimes incorporated by leaving suitable gaps or installing topsoil bags as occurs with crib walling, but this may not always be feasible.
The extension of the Rover plant in Solihull required excavation into an existing slope on site. A 70° steep slope was constructed and reinforced with soil nails. A sprayed concrete facing was installed which spanned the soil nails and included the provision of “crack inducers” and expansion joints .
- BS EN 14475:2006 Execution of special geotechnical works – reinforced fill
- BS EN 1997-1:2004 Eurocode 7: Geotechnical design
- BS 6031:2009 Code of practice for earthworks
- BS 8002: 1994 Code of practice for earth retaining structures
- BS EN 15258:2008 Precast concrete products. Retaining wall elements
- CIRIA Publication C516 Modular gravity retaining walls - design guidance, London 2000
- CIRIA Publication C516 Modular gravity retaining walls - design guidance, London 2000
