Project Sheet: Wrexham Gateway
- Richards Moorhead & Laing Ltd
- Alun Griffiths Contractors Ltd
- site investigation
- excavation of trial pits and boreholes
- provide geotechnical recommendations for the development
- design a highway embankment
Description of Project
Wrexham County Borough Council proposed the re-alignment of Croesnewydd Road onto a newly constructed embankment. It was to replace the existing masonry bridge constructed over the old railway line. A new junction was also proposed off the embankment to provide access to the Wrexham Western Gateway development which was under consideration at the time.
GroundSolve Ltd were asked by Richards Moorhead & Laing Ltd to assist them with the realignment of the road and the construction of a replacement culvert beneath the embankment to carry the River Gwenfro which originally passed under the road.
Previous site investigations had been carried out on behalf of Redrow Homes prior to the Wrexham Western Gateway development.
Boreholes and trial pits were also excavated as part of the site investigation organised by GroundSolve Ltd. Soil samples were taken to be assessed in a laboratory to measure both the physical and chemical composition of the soil. The exploratory holes indicated that the ground strata comprised topsoil and alluvium deposits, clay, glacial sand and gravel.
GroundSolve Ltd were required to design the highway embankment which involved the production of earthworks specification and drawings and carrying out slope stability analysis.
The land enclosed by the existing and proposed roads was low lying with two stockpiles to the north east. The stockpiles were derived from the housing development to the south west of the area and were considered suitable for providing some of material for the construction of the embankment.
The new embankment lies immediately to the southeast of the original road, and the previous road and culvert have been removed over the entire length of the re-alignment.
Environmental and Sustainability Issues
The site was visited in February 2011 by an Entec ecologist, who was commissioned by Bam Construction, to undertake an initial appraisal of potential ecological constraints on the site. The majority of the species and habitats recorded were of limited concern to conservationists. However, evidence of otters had been recorded in the River Gwenfro that crosses the site, as well as the pond to the north west of the site. An Ecological Impact Assessment concluded that the river and pond were important. Therefore, all site work needed to include measures to minimise effects on the otters, to maintain an undisturbed corridor during the works.
Another issue was that flood water follows the line of the disused railway, which runs across the northern boundary of the site where the embankment was to be built. The new junction would now hold it back.