Highways England makes case to build world’s longest road tunnel
A tunnel under the Pennines to provide a new road link between Sheffield and Manchester is technically feasible and worth exploring further, according to Highways England engineers.
Above: The Trans-Pennine tunnel could be even longer than Norway's 24.5km Laerdal Tunnel
At between 20km and 30km, potentially, it could be the world’s longest road tunnel, but it could be done, and might deliver economic benefits of up to £421m a year, initial studies suggest.
The two longest road tunnels in the world are: Laerdal Tunnel (one bore of 24.5km) in Norway, which opened in November 2000; and Zhongnanshan Tunnel (two bores each 18km) in China, which opened in January 2007. The experiences and knowledge gained from constructing these long road tunnels are being applied to this study.
On the technical issues, the report says: “The construction of a new strategic road link involving a substantial length of tunnel is technically feasible. Modern tunnelling techniques can accommodate a dual carriageway tunnel and the geology of the Pennines is generally suitable for constructing large diameter ores. Various tunnelling methods are available, including the use of TBMs for diameters up to around 15 metres, drill-and-blast techniques and, potentially, cut-and-cover sections. We will consider the cost and environmental impacts of these tunnelling methods for each potential route option.