Beauly Denny

Richard Pennock

Richard Pennock


Tel: 01423 276000 Email


Babcock Networks (on behalf of Scottish Power Energy Networks)


  • Preliminary Risk Ranking Assessment
  • Ground Investigations at Proposed Transmission Tower Locations
  • Access Track Investigations
  • Project Management
  • Interpretative Report

Ground investigations at proposed transmission tower locations

A new overhead line (OHL) is to be constructed by Scottish Power Energy Networks (SPEN) to run between Beauly in the Highlands to Denny in Stirlingshire, Scotland. CGL was appointed by Babcock Networks, acting on behalf of SPEN, to undertake ground investigation works along a section of the new OHL bordering Stirling.

This section of the OHL comprised 74 new towers requiring boreholes at each new tower location along with trial pitting works along the alignment of each proposed construction access track.

The investigation comprised three distinct areas: a mountainous northern section, ‘carse’ low lying agricultural land in the centre, and undulating land to the south. Following a desk study and a preliminary geotechnical risk ranking assessment, it was proposed to utilise two different drilling techniques: combined percussive/rotary drilling on the northern and southern sections where bedrock was anticipated close to the surface, with cable percussive drilling in the central location where extensive drift deposits were likely.

CGL acted as project manager for the ground investigations along the route, working closely with Babcock to overcome access issues, which included the restriction of any wheeled vehicles to sections of the site, inclement weather and ecologically sensitive sites including peat bogs.

Following completion of site works, CGL again worked closely with the Babcock Design Team to provide an interpretative geotechnical and geoenvironmental report detailing geotechnical parameters for foundation design purposes along with a semi quantitative contamination assessment. In addition, CGL provided an updated geotechnical risk ranking assessment identifying any issues highlighted during the ground investigation works.