Rogfast: Norway's 27 km subsea tunnel pushing civil engineering to the limit

Overview

The B1M takes viewers to Norway’s rugged west coast to explore Rogfast, a 27 km twin bore subsea road tunnel under Boknafjord that will transform the E39 coastal route. The video highlights the scale of the project, the unique geology of Norway’s fjords, and the innovative tunneling methods that are enabling this record breaking infrastructure.

• Worlds longest and deepest subsea road tunnel
• Three construction sites with a world first island interchange
• Norwegian tunneling techniques drive progress over traditional TBMs
• Comprehensive ventilation and safety systems across the route

Introduction and context

The Rogfast project sits on Norway’s west coast along the E39 corridor, aiming to connect Stavanger with the broader European road network by crossing Boknafjord with a dual bore subsea tunnel. This undertaking responds to the region’s heavy industry and the need to improve a highway that currently requires ferries and multiple tunnels between fjords. Rogfast is designed to minimize ferry dependency and create a continuous, safer route across one of Europe’s most challenging coastal landscapes.

Geography and engineering scale

The video emphasizes the epic scale of crossing a coastline punctuated by fjords carved by ancient glaciers. Sulefjorden, for example, presents depths up to around 400 meters, making conventional tunneling or single span bridges impractical. Rogfast comprises two 27 km bores that run through three main sites: the southern tunnel from Stavanger, the northern leg, and the Kvitsoy island interchange area. At its deepest point the tunnel will sit approximately 388 meters beneath the fjord, with the overall route extending across multiple rock bands and fault zones that complicate excavation and support. This is paired with an adjacent, parallel tunnel, forming a highly complex underground network designed to serve as a cornerstone of Norway’s coast road system.

Rock, geology and tunneling method

A central theme is geology. Across its length the tunnel passes through several rock bands with fault zones that have produced highly fractured and water bearing ground. Phyllite is dense but not suitable for structural use, while northward gneiss contains pressurized water pockets, making the geology highly unpredictable. Because of these conditions, Rogfast does not rely on a traditional tunnel boring machine (TBM). Instead, it employs the Norwegian tunneling method, centering on drill jumbo based drilling and blasting. Four robotic arms on the jumbo feed drill bits into the rock face, and after each blast, rock rubble is removed. A waterproof membrane is sprayed, bolts are installed, and the tunnel is lined with concrete panels, with as many as 60,000 panels planned for the project. This approach allows rapid adaptation to changing rock conditions as the face advances meter by meter, a process described as painstakingly precise and highly iterative.

Ventilation, safety and life lines

Long tunnels demand robust ventilation. Rogfast will be equipped with hundreds of jet fans and ventilation towers on both shores to maintain air quality and safe working conditions. A key mid route feature is Kvitsøy, where a large ventilation shaft is being constructed to deliver fresh air deep into the tunnel. The shaft construction begins with a pilot hole, followed by a large diameter drill bit and a 9.5 meter wide excavation, then excavation from the bottom and shaft lining. The project uses extensive electrical and logistical infrastructure to keep operations running, including a land based workshop that travels down the tunnel as work progresses.

Interchange and local benefits

The Kvitsøy interchange is described as a crown jewel of the Rogfast project. It integrates two tunnel faces with ring roads, slip roads, and cross passages, creating a highly complex underground junction that connects with a new island and an expanded road network. Beyond connectivity, the project will reclaim land from the sea using rock excavated from the tunnel and has driven road upgrades in the region, including new bridges that improve local transport and economic prospects for Stavanger and surrounding communities.

Conclusion

Rogfast is presented as not just a feat of scale but a testament to how civil engineering negotiates with nature. The project represents a generational leap in tunneling strategy, ventilation, safety, and community integration, positioning Norway as a leader in subsea infrastructure. While the technical challenges are enormous, the video frames Rogfast as a blueprint for even larger ambitious endeavors in the future, pushing the boundaries of what is possible in underground transportation networks.