SuDS Retaining Wall Case Study

Attenuation Pond, Webwall Geocell, Bellway Homes, Nottingham, UK

Project Information

Client:Bellway Homes
Contractor:Geogreen Solutions
Consultant:Stephen Daykin Cons/GRM/JPA
Product:Webwall Geocell, Abgrid Geogrid , Fildrain, Erosamat 1 Erosion Control Matting
Quantity600m2 face of wall
Benefits:- Use locally won fill saving on cost and environmental impact
- Green integrated solution
- Versatile flexible profile


Project Description

Bellway Homes developed a new northern suburb of Nottingham on a greenfield site near Arnold.

The Challenge

Typically, planning consents are granted based on SuDS retention equivalent to a green field site. For reasonably large developments, such as this, the volume of water accumulated from rain run-off would mean sizeable ponds using up valuable building land. The designer proposed a basin with steep slopes to save space; the lower portion at 60 degrees and the upper 30 degrees. The challenge was to provide a steep wall with a green finish which can withstand surface run-off erosion and be structurally sound at minimum cost.

The Solution

ABG offered Webwall® geocell as it uses locally won materials to stabilise weak or low cohesion soils. Laid in horizontal layers, infilled and compacted using site won materials, Webwall® geocell was shaped to fit local contours and fitted neatly around the outfall structures. This avoided the costly importing of aggregates and reduced the impact on the environment from the extraction and transport of aggregate to site. During build up and filling, the front cells are filled with topsoil to encourage growth in the front cell once construction is complete. Vegetation on the face gives a pleasing visual impact and improves system longevity.

The wall needed to be stable during construction and service. Calculations showed that layers of Abgrid geogrid were needed for wall heights above two meters.

As these ponds are at the bottom of a series of swales, there will be a higher water table at times of heavy rain. Strips of Fildrain drainage gecomposite are included behind the Webwall® geocell to provide drainage for ground water flows to prevent saturation of the reinforced section of the structure.

The Abgrid geogrid alone was used to reinforce the upper slopes and the face was protected from surface erosion with Erosamat® Type 1 erosion control matting while vegetation established. The overall construction was finished on time, within budget and to specification and will form a green civic amenity in the midst of a new urban development.

ABG Webwall geocell, Fildrain drainage geocomposite & Abgrid Geogrid uses in a steep sloped green wall application

ABG Webwall geocell, Fildrain drainage geocomposite & Abgrid geogrid used in a steep sloped green wall application.

Webwall Geocell and Abgrid geogrid constructing a green steep wallLayers of Abgrid geogrid and Webwall geocell are progressively built and backfilled with locally won fill. The front cell is filled with topsoil and planted. The Webwall is shaped to fit with headwall structures
Geocells used for steep vegetated slopes on a SuDS attenuation pondFinished structure with upper slopes reinforced with Abgrid and surface protected with Erosamat Type 1
Grass and vegetation covering the Webwall geocell stabilised slopesFinished pond starting to green and blend with the natural environment

The ABG Service

ABG offered a full turnkey design, supply and installation package (installation by the ABG subsidiary, Geogreen Solutions). This package was chosen based on the technical proposal, meeting the construction program and ultimately cost effectiveness.

Contact ABG today to discuss your project specific requirements and discover how ABG past experience and innovative products can help on your project.

Webwall Geocell

ABG webwall is a flexible geocell retaining wall system that utilises geocell technology. Using Webwall geocell for green faced walls with near vertical faces can be built quickly and easily with the added benefit of using site won materials as fill

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Webwall green wall earth retaining wall soil confinement geocell system
 

Products

Webwall Geocell

ABG webwall is a flexible geocell retaining wall system that utilises geocell technology. Using Webwall geocell for green faced walls with near vertical faces can be built quickly and easily with the added benefit of using site won materials as fill

more...

Webwall green wall earth retaining wall soil confinement geocell system
 

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