Earthmoving contractor completes initial groundworks for overhead section of Hinkley Point Connection
IN 2020, earthmoving contractors Kelston Sparkes were awarded the groundworks contract for the overhead section of the Hinkley Point Connection project. The contract was for the southern section of the innovative National Grid project to create a new high-voltage electricity connection between Bridgwater and Seabank, near Avonmouth.
The connection, some 57km long, comprises 48.5km of overhead lines and uses the world’s first operational T-pylons. The remaining 8.5km of cable runs underground through the Mendip Hills AONB, leaving it free of pylons for the first time since the 1960s. Upon completion, the connection will provide new sources of low-carbon energy for homes and businesses in the South West.
Working for Tier 1 contractors Balfour Beatty, the work on the southern section stretched from south of Bridgewater to Biddisham and entailed the installation of around 12km of temporary haul roads and the construction of 45 work areas (a combined piling mat and crane platform area) across the Somerset levels ready for the erection of the pylons.
The unique nature of the low-lying levels meant that the work included building a network of ditches, damning off and reaming multiple water courses, and constructing culverts to divert water under the haul roads. Each watercourse required a bespoke solution and careful planning to ensure all measures were reversible at the end of the project.
With sustainability at the heart the scheme, Kelston Sparkes partnered with a novel company called Soil Science to minimize the aggregate requirement for the haul roads and work areas. Whilst the original design required the stripping of the topsoil and laying geogrid and 6F5 aggregate, Soil Science developed the SUREGROUND reversible soil-enhancement system, which mixes in-situ site soils with a proprietary binder to stabilize the soil and increase the load-bearing capacity of the ground.
By embracing this technology, it was possible to reduce the size of the soil storage areas and eliminate the requirement for large quantities of primary aggregates, reducing both installation time and lorry movements and vehicle-related emissions. This, together with reduced noise, dust and vibration levels, helped ensure community relations were preserved. Ultimately, 50% of the whole scheme was completed with the SUREGROUND temporary stabilization solution, which is fully reversible.
With installation of the southern section now complete, the team from Kelston Sparkes is currently back on site to remove the haul roads and the and carry out the reinstatement. Contracts director David Swann confirmed that, thanks to the experience gained and the successful delivery of the initial section, the company has since tendered for and started work on the northern section of the project.
‘We were delighted to win the tender to deliver the overhead section of this prestigious project and to continue strengthening our partnership with Balfour Beatty,’ said Mr Swann. ‘This project played to our strengths, enabling us to produce the required aggregates within the quarries where we currently operate, undertaking all the transport and placing of temporary roads and work areas, and then finally removing and repurposing the aggregate on other projects, thus significantly reducing the overall carbon impact. It’s been fantastic to work with Soil Science, who enabled us to deliver a really sustainable solution with their innovative soil-enhancement system.’