Research pick: A bit like a bridge under troubled water - "A review of research developments on submerged floating tunnel"

Researchers writing in the International Journal of Critical Infrastructures discuss the potential engineering solutions for building a submarine tunnel as part of a future transport infrastructure.

A submerged, but floating, tunnel could be the answer to linking infrastructure between places separated by bodies of water. The approach precludes the need for digging the tunnel beneath the floor of the body of water, whether river, lake, or sea. However, the engineering requirements are immense and any such structure must be stable to current and corrosion as well as freak incidents such as tsunami.

Sahil Rana and M. Abdul Akbar of the Department of Civil Engineering at the Dr. B R Ambedkar National Institute of Technology in Jalandhar, Punjab, India, point out that there have been proposals for submerged, floating tunnels in the past. Current computer-aided design and software can simulate the stresses and strains a civil engineering structure might experience in the real world under different conditions. This means it should now be possible to determine whether a given design and siting is feasible.

The team has undertaken a comprehensive review of the various engineering analyses so far performed on putative submerged floating tunnels. The review covers work from this multidisciplinary domain of transportation engineers, geotechnical engineers, offshore engineers, structural engineers, mechanical engineers, and others. The researchers have also reviewed the different policy-based conclusions regarding this novel transport technology. Their conclusion is that such tunnels will ultimately revolutionise connectivity and transportation. Such tunnels could have a major impact on joining island clusters, for instance, or connecting regions where a spanning bridge would be inappropriate or impossible.

They point out that there are not yet and standard ways to look at submerged floating tunnels and much work needs to be done in terms of anchorages and tethers as well as understanding the response of such tunnels in use in a body of water. The team adds that the impact of such potentially enormous structures on aquatic life, particularly large organisms must also be considered be these tunnels are launched.

Rana, S. and Akbar, M.A. (2023) ‘A review of research developments on submerged floating tunnel’, Int. J. Critical Infrastructures, Vol. 19, No. 1, pp.58–78.