Anglesea Landfill, operating since 1974, is a Type 2 ‘valley fill’ landfill accepting approximately 20,000 tonnes of waste including putrescible waste, solid inert waste and fill material.
The site comprises the Original Cell, Cell 1 and Cell 2. The Original Cell has been filled to capacity. The eastern side of the Original Cell has been rehabilitated with a soil cover and southern part of Cell 1 has being rehabilitated under Stage 2 rehabilitation works. Cell 3, which is piggybacking Cell 2
(Stages A and B) has been constructed up to Stage C and is currently receiving waste.
A civil works contractor with experience in waste projects, particularly landfill rehabilitation and construction, was appointed to construct a new cell liner (Cell 3 Stage D – Liner) plus completion of the Stage C Sideliner (Bund Wall) Extension. To increase the height of the bund wall, a retaining structure was required. The Reinforced Soil Structure (RSS) specified for the Bund Wall height extension is up to 5 m high and 105 m long.
For the RSS, Geofabrics proposed the Maccaferri Green Terramesh® system by highlighting the advantages i.e. unmatched speed of installation, cost effectiveness and proven performance. Based on these key benefits and using previous project case studies, the Geofabrics’ proposed solution was selected. The Green Terramesh® solution is an environmentally friendly option typically used to form vegetated faced reinforced soil slopes (also known as Mechanically Stabilised Earth) and embankments.
The system consisted of pre-fabricated units of double twisted wire mesh stiffened with a welded mesh panel. Two integral pre-formed steel braces maintain the unit to the required slope angle, which in this case was 70 degrees.
Paralink 200 (200 kN/m) geogrid was included at each Green Terramesh® layer to augment the strength of the double twist wire mesh. As per the Paralink British Board of Agreement certificate 03/4065, creep reduction factors are available for design temperatures up to 40˚C, installation damage factors for a D90 particle size up to 150 mm and chemical effects for pH of soil up to 11. This makes Paralink geogrids particularly suited to landfill and tailings dam applications.
As all components are factory fitted, Green Terramesh® was rapid to install. The unit was simply erected on site with the bracing angles supporting the face at the designated angle without the need for any external formwork or shuttering. Structural backfill was placed upon the soil reinforcement geogrids, and a loose rock veneer was stacked on the inside face of the Green Terramesh® which negated the use of topsoil or an erosion control blanket.
Included in the initial proposal to the contractor, Geofabrics supplied a comprehensive installation manual. The contractor said the system was quick and easy to install.