Hinkley Point C - Fish Return

Tunnelling and Underground Works Marine and Landfall Works
Value:
£700m
Sector:
Energy
Client:
NNB, Kier Bam
Duration:
18 months
  • 1.8m Diameter, 620m Sea Outfall Tunnel

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Project description

At Joseph Gallagher, we are appointed to undertake a technically demanding 1.8‑metre‑diameter, 620‑metre sea outfall tunnel, constructed using a pipe‑jacking methodology. The project requires the controlled installation of a closed‑face TBM that is later recovered above the seabed, a task which demands absolute precision, careful planning, and specialist offshore capability throughout the operation.

Our work involves driving the tunnel from a restricted launch site and managing a complex alignment that includes double vertical curves and a challenging angled breakthrough. The TBM progresses through varying geological conditions before entering a 45‑metre‑long offshore concrete structure, where the breakthrough and recovery operations are carried out in a marine environment that is frequently influenced by adverse weather and significant tidal variation. To maintain progress under these conditions, we adopt a closed‑face tunnelling method supported by a separation system that allows the complete recycling of process water, meeting both the technical and environmental requirements of the project.

JGL at Hinkley Point C Fish Return

The project presents a range of engineering challenges, including limited space at the launch site, an angled TBM drive through varying ground conditions, and the need for high-precision navigation along complex vertical curves. These are further complicated by marine constraints such as tidal fluctuations, weather conditions, and the requirement for hyperbaric interventions under elevated pressures.

We address these challenges through our specialist tunnelling expertise, using advanced gyroscopic guidance for precise alignment, safe and efficient hyperbaric operations, and dedicated offshore systems for TBM recovery.

A fully integrated approach ensures continuous progress, supported by sustainable practices such as full process water recycling, reuse of tunnel arisings, and the use of environmentally responsible materials. Backed by in-house equipment and a collaborative delivery model, the project is executed safely, efficiently, and in line with programme and budget targets.

JGL at Hinkley Point C Fish Return working day
JGL at Hinkley
JGL at Hinkley Point C - pipes launch
JGL in Hinkley Point C - work in the progress
JGL works at Hinkley Point
NRC works at Hinkley Point C

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To hear about our experiences and how we can help you.

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