A MULTIFUNCTIONAL geogrid is getting its first big UK use during installation of a landfill cell for a chemical plant in Grimsby.
The TRC-grid, developed in the Netherlands by Akzo Nobel Geosynthetics, and supplied in the UK by MMG Civil Engineering, is designed to provide the reinforcement properties of a conventional geogrid with the separation and filtration function of a geotextile.
The grid is made of aromatic polyamide, a material relatively new to geosynthetics, which is light and easy to handle, yet provides high stiffness in the grid bearing members. The polymide is embedded in a polyester nonwoven filter layer.
It is also being used on a project for Millennium Inorganic Chemicals (MIC) which is expanding operations at its Stallinborough plant. The company produces the brilliant white titanium dioxide pigment for paint and plastics, and operates its own landfill disposal operations to keep control of manufacturing waste products .
MIC asked AIG Consultants to make an environmental impact assessment so it could apply for planning permission for the necessary landfill expansion. MIC environmental manager Brian Crocker says this should allow cost savings to be made and the company to have more control of its waste streams.
AIG also won the contract to design the new landfill cell, which will be used to deposit non-hazardous industrial waste such as neutralised filter cake, construction and demolition waste and plastics. It is the third cell to be built, with the potential for expansion included in the planning permission.
'The entire facility has the potential to give us a 20 year life capacity if it is fully developed,' says Crocker.
Beneath the site is firm to stiff clay over softer alluvial estuarine clay. AIG senior engineer in charge of the project, Rob Howells, says there were some concerns over differential settlement as the cell was filled. To minimise this it was decided to use geosynthetic reinforcement in Type 1 gravel as a support to the lining system which consists of a geosynthetic clay liner overlain by a flexible membrane liner and geotextile protector.
Main contractor Cheetham Hill Construction started site work in mid- May and is due to finish this month.
The geogrid will cover the base of the 100m by 40m cell which will eventually hold up to 7m of fill at its deepest point, with a final (probably geosynthetic/clay mix) capping layer.