Landfill Drainage Case Study

Capping Steep Slopes, Pozidrain G, Silent Valley Landfill, Ebbw Vale, UK

Project Information

Client:Silent Valley Waste Ltd
Contractor:Jim Davies Civil Engineering
Consultant:Arup
Product:Pozidrain G7SD surface water drain and Pozidrain G4SD gas drain
Quantity65,000m2 & 60,000m2 respectively
Benefits:- Enhanced friction
- High flow capacity in both directions
- Membrane protection


Project Description

Silent Valley, which runs up from the Welsh town of Ebbw Vale, is being restored and turned into a nature reserve managed by the Blaenau Gwent County Council and Gwent Wildlife Trust. The once post-industrial mining valley, contaminated with metal recovery waste has been cleaned up and the upper valley turned into a modern domestic landfill facility which is capped off and landscaped to become part of the nature reserve. Silent Valley is now one of the most beautiful natural environments in Gwent.

The Challenge

With the finished landfill profiles incorporating 80m long 1 in 2.5 slopes the challenge was to achieve a stable cap without any reprofiling or use of geogrid reinforcement. The aim was to install a multi-layered synthetic cap comprising a 1mm LLDPE textured geomembrane with a drainage capability above the membrane and a gas venting capability below.

The challenge was to provide sufficient drainage capacity on both interfaces and adequate interface shear strength to withstand the dead load of the 0.5m cover soil and live load of the construction traffic whilst placing the backfill material on this critical slope.

The required slope stability was not possible to achieve with standard geocomposites typically used for the landfill cap drainage. A geocomposite with enhanced performance was required for this 1 in 2.5 slope application.

The Solution

The unique Pozidrain G geocomposite was used to provide drainage, gas venting and membrane protection. Pozidrain G drainage lattice provides additional interlocking and enhanced interface friction with cover soil material on steep slope installations. It has sufficient flow capacity in both long and cross direction to drain cover material and ensure slope stability. Shear box tests against site specific cover soil material and LLDPE geomembrane confirmed adequate Pozidrain G interface friction performance. The project was finished on time and at optimum cost resulting in an area fit for a nature reserve.


ABG Pozidrain G Drainage Geocomposite for landfill applications

ABG Pozidrain G Geocomposite with enhanced frictional properties specifically designed for steep slope installations above and below a capping liner.

Pozidrain protects the landfill's geomembraneProving high friction as construction traffic spreads cover soil whilst protecting the geomembrane
Drainage in all direction provided by the geocompositePozidrain G with drainage in all directions placed on top of 1mm LLDPE textured liner
Finished grass finished slopes of the landfill capFinished, permanently stable, aesthetically pleasing green slope

The ABG Service

ABG proposed the system and provided design and site specific laboratory test results. Site support during the construction and timed deliveries ensured a successful construction.

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

Pozidrain G Geocomposite

Geocomposite for landfill cap drainage, gas-venting, ground water drainage and leachate management. Particularly useful on steep slopes where its core structure offers enhanced frictional performance whilst providing protection to the lining system.

more...

Pozidrain G Geocomposite
 

Products

Pozidrain G Geocomposite

Geocomposite for landfill cap drainage, gas-venting, ground water drainage and leachate management. Particularly useful on steep slopes where its core structure offers enhanced frictional performance whilst providing protection to the lining system.

more...

Pozidrain G Geocomposite
 

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