RamArch
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Project: Netherton Canal Tunnel Refurbishment
Owner: Canal & River Trust
Designer: Jacobs Associates & OTB Engineering
Contractor: May Gurney
Purpose: Strengthening of a brick-lined canal tunnel lining.
RamArch Type: Plain steel 8mm RamArch mesh, manufactured to BS standard.
RamArch finish: Fully encapsulated in shotcrete.
Date: 2013.
Netherton Canal Tunnel was constructed in the 1850s, and this 2.77-kilometre long, brick-lined tunnel is one of the largest and deepest canal tunnels in the UK and was, at the time of its completion, one of the longest and deepest in the world. Tow paths on either side of the tunnel are also used as pedestrian walkways. Since its construction, it has had a history of ground movement and lining deflections, with several phases of minor to major repair work having been carried out to maintain navigability and safety.
Towards the centre of the alignment, Netherton Canal Tunnel is about 120 metres deep, which has resulted in substantial ongoing stress-related tunnel lining deformations. This depth and the surrounding geology contribute to significant pressure on the structure, making maintenance a persistent challenge. Several major repairs had been carried out to sections of the tunnel where deformations became so excessive that boats were unable to pass through. More recently it was decided that this important asset required extensive refurbishment over a large part of the tunnel, generally using rockbolting to stabilise the structure and mitigate further damage.
However, in the most active central section, a reinforced sprayed concrete arch supported on raking micropile and anchor foundations was designed, incorporating RamArch as its primary reinforcement system because of its ease of handling, simplicity, and speed of erection. This solution not only addresses the immediate structural concerns but also ensures long-term resilience against future stresses, safeguarding the tunnel’s operational integrity and historical significance for generations to come.
Interested in learning more about how RamArch can enhance your project?