Cabot Park - Avonmouth

Key groundworks to support a roadway serving a major industrial area have benefited through the use of Leca® lightweight geotechnical fill as a solution to dealing with soft and contaminated land.

The RD Park, Merebank, Avonmouth project, to provide new warehouse units with ancillary offices, was constructed on a brownfield site, which formerly housed chemical and smelting works. John Sisk & Son Ltd, main contractors for developers Rosemound Developments Ltd, originally intended to use traditional aggregates and general fill to support an adoptable highway into the site. However, when it became clear that this would produce far greater than desired overall settlements on the soft alluvial clay, TDHA Ltd, consulting engineers, of Birmingham, were asked to develop a lightweight solution capable of substantially reducing settlements, which would be easy to install. TDHA Ltd decided that a combination of a geotextile/geogrid "carpet" across the sub-formation, followed by the installation of layers of Leca® fill 10-20mm, would provide a solution capable of falling within the required settlement and loading limits. The proposal also tied in with the design for the planned remediation of the contaminated sub strata. To improve delivery and reduce environmental impact, the Leca® was shipped into Avonmouth Dock situated just one mile from the site. Construction sequencing limited the space available for access and just two 55m³ wagons were placed on turnround to deliver approximately 750m³ per day.