News

Cities are starting to run out of free space. By 2060, the world’s population will exceed 10 billion people, according to predictions of the United Nations. Population growth, migration and climate changes cause that in the future the use of underground infrastructure may become a necessity. Tunnels are a well-known invention, but is it possible to move almost an entire city underground? An expert from ILF Poland answers this question.

Tunnels and their advantages

The world-famous underground transportation tunnels allow to shorten the way or make it easier. A ride through a long route, drilled into a massive mountain, is always a great attraction and variety for traveling people. However, not only such tunnels are available to us – we can also move under the bottom of the river or the sea. The English Channel, connecting Great Britain and France, which length is over 50 kilometers, is a very important investment, allowing free travel between these countries, without having to build complex port infrastructure.

Building tunnels is expensive, but I think they are the future. They have one great advantage – they can hide underground what we don’t need on the surface, such as car traffic. This is important, because then we do not interfere with green areas, we do not collide with what people would like to do on the surface. A tunnel usually shortens or eases our way – says Marcin Przepiórka, Deputy Director, Transport Infrastructure Area, ILF Consulting Engineers Polska. For example, the tunnel under Swina River allows fast, unhindered traffic in both directions, without involving port infrastructure. In the case of mountainous areas, the tunnel clearly shortens the distance to be travelled,” he explains.

More and more often, besides the construction of underground tunnels, there are growing ideas to bring more parts of cities, and especially their infrastructure, into the underground world.

Will we be living underground?

The idea of hiding (almost) entire cities underground starts to be more and more boldly presented and discussed on the world stage. Of course part of the infrastructure will still remain on the surface, such as residential buildings, parks or bicycle paths.

There’ s a trend forming that not only tunnels, but entire cities can be brought underground. Of course, this is a certain metaphor, because it is not possible to literally hide everything below the surface of the earth – people need daylight to live. However, nothing stands in the way of moving all the traffic, like the metro, below. We can also add all the networks necessary for the city to operate, which is already happening, or for example water reservoirs – in fact everything that is possible and not necessary on the surface – explains Marcin Przepiórka, Deputy Director, Transport Infrastructure Area, ILF Consulting Engineers Polska. In the above ground part we will keep green areas, residential buildings, parks, sidewalks. The result is a green city, a city with zero noise emissions, because underground traffic can be dampened, and if we enter the era of electric cars in transport, the problem will be completely eliminated. With proper ventilation of underground spaces, we can create cities that are pollution-free,” he concludes.

It’s already happening

Plans for underground cities are already being prepared, and their projects are being created on a grand scale. The Line – the linear city of the future – will connect the Red Sea coast with the north-western corner of Saudi Arabia. According to the assumptions, about a million people will live in it, and its length will reach 170 kilometers! Despite this, it will be possible to provide all the basic needs of life within a few minutes’ walk. This possibility will remain thanks to the above-ground part, which will be an oasis for pedestrians and cyclists. Services and transport will be located underground. The cost of the entire investment is estimated at 500 billion USD.

However, looking at the investments of our western neighbors and those in Poland in a more down-to-earth way, it can be seen that the trend is noticeable.

In Germany, there is a trend to lay electrical lines underground, in tunnels. While the low voltage line does not require any special measures, the issue is more difficult with higher voltage (110-220 kV). We can’t lay a power transmission line in the ground, because the voltage is so high that it requires special tunnels,” says Marcin Przepiórka, Deputy Director, Transport Infrastructure Area, ILF Consulting Engineers Poland. There will be more investments of this type. The technology of building underground is becoming more and more popular – let’s look, for example, at the southern ring road of Warsaw, which is largely hidden under the surface. The process of transferring parts of the city to this zone is happening before our eyes – he adds.