A radical road tunnel project in the UK could cut the cost of construction. This would involve building a tunnel as much as 22km in length underneath the scenic Peak District National Park. It would provide faster connection between the cities of Manchester and Sheffield. Unlike previous proposals for a road tunnel, this would be less costly to construct.
Instead of the conventional TBM driven tunnel, drilling and blasting would be used instead. The proposers believe that drilling and blasting could the tunnel for £2 billion. This is far les than the £10 billion needed to build a tunnel using a large diameter TBM and securing the drive with segmented pre-cast concrete units.
Drilling and blasting
Driving tunnels using drilling and blasting is common in the Nordic countries, where much of the most modern technology for this methodology originates. The system is reliant on the presence of competent rock formations that can support the process. These are present in the Peak District. The method uses drilling and bolting to secure an arch-like effect around the bore and this is then shotcreted to cover the walls, with a lining added to seal the tunnel.
Alignment options
Three possible alignments were proposed for the tunnel previously. But the project stalled due to concerns over the high cost of using a TBM. Drilling and blasting could provide an option with a lower pricetag, with the link being tolled to pay back construction costs. A new tunnel would form part of the National Highways network and offer a sustainable transport option.
The UK’s Department for Transport has said that other methods for improving transport through the Peak District are more economic. These would involve improving existing roads.
