We delivered complex piling solutions to support the delivery of over 660 new towers on the 220km Beauly-Denny overhead line replacement project – Europe’s largest mini piling project at the time –helping connect up to 1.2 Gigawatts of renewable energy to the grid.
Supporting the delivery of the 220km overhead line replacement project, which stretches across the Scottish Highlands, we deployed seven mini piling rigs and a top drive rig to install a combination of drilled minipiles, top-driven steel tubes, and precast concrete piles. Minipiles were essential in the remote Scottish location that had shallow bedrock, however where access and ground conditions allowed, we used driven and precast piles to optimise cost and programme time.
Restricted access and the ranging geology of the site, which included Granite, Schist and Quartzit proved challenging on this project. Despite four rigs working on site, our initial progress to install the piles was slow. To improve the pace of installation and ensure that we would be able to complete the project on time, we re-engineered the foundation design to simplify installation and accelerate progress. To improve capacity and reduce the number of piles required, we reduced the rock socket diameter to 190mm by using a heavy Ischebeck bar. After reassessing the block failure, we were also able to reduce the overall drilling depth at each leg. The smaller pile diameter improved the quality of positional tolerance control and increased productivity by 50%.
To improve manual handling safety and precision during placement, our team also introduced a calibrated lifting device and adapted couplers to handle steel tubes. This innovation, combined with the revised pile design, significantly reduced cost, CO₂ emissions, and overall programme time.
With the majority of the work taking place during winter, a full winter programme and robust health and safety measures were implemented. This included the use of CB radios, satellite phones and specialist PPE to protect teams from the extreme weather conditions and terrain. Our team’s focus on health and safety ensured the project was completed with zero lost time incidents and an AFR of 0.
As part of our commitment to reducing waste and driving resource efficiencies we utilised locally sourced stone to build access tracks to minimise transport emissions and repurposed casing cut-offs across the site to reduce waste.
Mini piling
Discover our full range of mini piling techniques and how we deliver tailored technical solutions in the most constrained environments, to meet the site conditions.
