Stunned with the way Sweden built the longest tunnel in the world

When the E4 road tunnel is operational, it will regulate the amount of traffic that is already very crowded in Stockholm.

Stockholm is known to be more watery than roads. The whole spectrum stretches over 14 islands, where Lake Mälaren flows to the Baltic Sea. Living in an area surrounded by large water bodies, people here have a special affection for the lakes, rivers and natural forests stretching along the water. And it's not natural, Stockholm's air quality stands at the top of the world.

And it is these beauties that challenge the construction engineers here. They had to find a way to design and build a 6-lane road over 21km long, running from the North to the South, connecting the growing areas. How did these talented workers work to minimize the impact on this 21km long project?

"Normally, in an area with as few structures as we have here, we will build an above-ground road that follows the path that is needed, and place the bridge where necessary" , Johan Brantmark, Head of the E4 project of the Swedish Transport Management Board told ArsTechnica. "If so, things will be much cheaper and easier to implement. But we have other things of higher importance, at least to protect the environment around the project. Therefore, a tunnel Long will be the most effective option ".

The deepest point of the tunnel will be 80 meters above the surface of Lake Mälaren.

This solution requires about 18km of tunnel, with two travel directions, each direction must have at least 3 lanes. In total, the tunnel will be divided into 3 areas, the E4 tunnel project will avoid 6 natural areas that are culturally significant, including the background of Drottningholm Palace - a UNESCO-recognized heritage site, located at Lovö Island, besides that they do not need to cross the bridge over Mälaren, the clear water here will be protected.

And this E4 project will be one of the world's largest underground underground highways, with a total length of 16km. The deepest point of the tunnel will be 80 meters above the surface of Lake Mälaren.

"Construction will still be a standard drilling and blasting process , " Brantmark explains of the slow-on-tunneling method that should have been in use since 2014. The total project will take up 20 million tons of land. rock. This work is built from 3 points at the same time, currently the construction progress has reached 20%.

"The harder the rock, the faster we dig. Drilling and blasting don't take much time, but blocking the gaps to prevent water from spilling in is another story. If the stone is fragmented, we will need a lot. cement to plaster as well as support columns to ensure the tunnel is safe ".

This explosive tunneling method also affected more or less residents living on the ground.

This explosive tunneling method also affected more or less residents living on the ground. In order to minimize these effects, this tunnel project also includes the cost of reinforcing and soundproofing thousands of glass windows of households and businesses along the construction area.

Particularly to preserve the environment around the construction area, the project used 4.1 billion USD . Thomas Holmström, the project's chief environmental officer, explains: "We are aiming to complete this whole project with a 10% lower carbon footprint than expected."

The E4 project optimizes the use of steel, cement, . products that are manufactured using a low carbon emission method.

"That means cutting energy consumption with the same amount of greenhouse gases throughout the construction process, besides using better life-cycle materials - synonymous with adopting new products. ".

Cement itself absorbs CO2, but cement production has significantly polluted the environment. In order to overcome this problem, the E4 project optimizes the use of steel, cement, . products produced by the low-carbon emission method.

Another example of an effort to reduce emissions: instead of using trucks to transport underground soil, the project uses a long conveyor system, with up to 1.7 km, along with three berths. temporary ports for taking up the land, moving to the local treatment areas.

This E4 tunnel will have a total of 240 ventilation fans mounted on the ceiling.

This will be a 16km underground tunnel, with 6 traffic lanes, so the escape of emissions will be one of the most important aspects of construction. This E4 tunnel will have a total of 240 ventilation fans mounted on the ceiling, three gas exchange stations to circulate fresh air inside. At the hatches, four gas stations will bring polluted air up, not letting it focus on the ground area.

"Our calculations show that the air circulation is absolutely no problem, but there is still no policy or guideline for this in the tunnel, we are still completing the exhaust system, but we confident that he will have an environmentally friendly system , " said Holmström, chief environmental officer.

Expected in 2026, when this project is completed.

The E4 tunnel design team is receiving further assistance from designers of Umeå University, to investigate the passage in the tunnel which will cause short-term and long-term effects on the health of traffic participants. in the cellar.

With 3 lanes in one direction, about 16 meters wide, the tunnel was not crowded at all, and they built such a tunnel so that even future Swedish people could use it. It is expected that in 2026, when this project is completed, it will allow the vehicles that are currently crowded in Stockholm inner city to move more easily. By 2035, it is expected that there will be about 140,000 vehicles passing through this E4 tunnel every day.

A project of the future, a multi-kilometer long tunnel puts the environment first. Any country can learn some things from the beautiful city of Stockholm.