Alternative design proposal enhances cost efficiency
Dragages proposed an alternative design by combining the two tunnels into a single tube with a partition wall separating the twin rail tracks.
To minimise interference between the excavation and concreting works, a powerful conveyor system was set up, with a capacity of removing 800 tonnes of waste per hour. The method proved to be faster and cleaner than using trucks.
Total excavation took over one and a half years, with some 700,000 cubic metres of waste being transported off site to be used as fill material in another project.
This alternative proposed design allowed the construction programme to be shortened by six months and delivered substantial cost-savings.