Case Studies: Innovative access road design to reach Glenchamber Wind Farm (Scotland) on soft, peaty ground

Innovative access road design, employing Tensar’s TriAx geogrids, enabled lorries delivering turbine sections to reach the site of a new wind farm built on soft, peaty ground.

The 11 turbines of the Glenchamber Wind Farm in south west Scotland generate 27.5MW, enough to meet the demands of about 20,000 homes in Dumfries and Galloway.

Renewable energy company RES appointed main contractor Luce Bay Group to build the wind farm, which included widening 4.5km of local roads, plus construction of 5.9km of wind farm tracks and a new 2.8km access road across the peat bog surrounding the site.

The tracks and access road were on the critical path of the project, as they had to be ready in time for the arrival of the first turbine sections. As a result, they had to be economical and fast to build, plus they had to perform immedi-ately.

Excavating the thick, very soft peat and replacing it with site-won granular material to form a stable road foundation would have been time-consuming and expensive, so Luce Bay and its geotechnical consultant JNP Group worked with Tensar International to come up with an alternative solution.

This comprised Tensar’s TriAx TX170-GD geocomposite laid beneath the granular road base and TriAx TX160 ge-ogrid incorporated within it, to form a mechanically stabilised layer. The TriAx geogrid interlocked with the granular particles, confining and restraining them from moving laterally. This increased the aggregate’s bearing capacity and delivered roads able to carry the heavy construction loads.

Luce Bay Group Project Manager David McCracken commented: “Not only did the design ensure the access roads were ready for the arrival of the first turbine sections, but it will also enable the road to perform throughout the oper-ational life of the wind farm, with minimal maintenance.”

Client benefits:

  • Efficient access road design over deep, soft peaty ground
  • Minimising the use of site-won aggregate
  • Enabling on-time delivery of wind turbines
  • Construction and operational performance, with minimal maintenance.

Tensar TriAx geogrid was incorporated into the road’s granular surface to create a mechanically stabilised layer.

The access road had to be capable of supporting lorries bringing the turbine sections to site.

Further information

For more information visit www.tensar.co.uk

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