Major Breakthrough! Serbia’s Longest Tunnel Completes Twin-Tube Excavation

On December 4, the Iriški Venac Tunnel financed by the Export-Import Bank of China and undertaken by CRBC achieved twin-tube breakthrough. It is a key control project of the Novi Sad-Ruma Expressway in Serbia. As the longest tunnel in Serbia, it is a vital transportation artery long awaited by the Serbian people, connecting the capital Belgrade with the country’s second-largest city, Novi Sad. Its breakthrough represents a major milestone, removing a key bottleneck for the project’s scheduled completion.

Located within the Fruška Gora National Park, the tunnel features a two-way, four-lane separated design and spans approximately 3.5 kilometers with a maximum burial depth exceeding 220 meters. It faced challenges often described as an “encyclopedia of geological complexities”, including soft surrounding rock, fractured fault zones, shallow overburden with asymmetrical loading, and water-rich sections. These conditions, coupled with high technical difficulty, significant risks, and stringent environmental requirements, made the tunnel the top priority of the entire project. After the right tube achieved breakthrough in October 2025, the project team steadily advanced work on the left tube through systematic optimization of construction planning and enhanced whole-process control. The left tube breakthrough was ultimately achieved safely, with high quality, and on schedule. This milestone marks the near completion of tunnel excavation. The project now moves into an accelerated phase, where multiple disciplines and processes—including secondary lining, electromechanical equipment installation, and pavement paving—will proceed in a coordinated manner. The project has entered the home stretch of construction.

The successful breakthrough of the Iriški Venac Tunnel stands as a flagship example of China-Serbia infrastructure cooperation and friendship under the Belt and Road Initiative. It demonstrates CRBC’s strong capabilities in technology integration, project management, and reliability in delivery in complex environments. Once opened to traffic, the tunnel will dramatically reduce travel time through the Fruška Gora Mountain Range from the current 30 minutes to just about five minutes. This will not only facilitate public mobility but also boost regional logistics, industrial layout, and tourism, injecting new impetus into Serbia’s social and economic development. Today, a future road representing safety, convenience, and green travel has broken through the mountains. It not only shortens the distance between cities but also connects opportunities for development and a shared vision, heralding a broader future for China-Serbia cooperation.

The project owner, the supervising engineer, the head of CRBC Central and Eastern Europe Regional Center and Serbia Office, along with the management team and construction workers, witnessed this exciting breakthrough moment.