The longest mountain tunnel worth 1.6 trillion on the North-South expressway
The Cam Lam – Vinh Hao expressway project is one of the three component projects of the East Coast North-South expressway project (total investment capital: 146,990 billion VND).
The Cam Lam – Vinh Hao project was started in November 2021 with a total investment of 8,925 billion VND and a construction period of 24 months. The project starts at Km 54, behind the Cam Ranh intersection in Cam Thinh Tay commune (Cam Ranh City, Khanh Hoa province), and ends at Km 134 + 00, at the Vinh Hao intersection, coinciding with the starting point of the Vinh Hao – Phan Thiet component project (Vinh Hao commune, Tuy Phong district, Binh Thuan province).
The road is designed according to the standard of a high-speed car road, with a phased investment scale of 4 lanes, a roadbed width of 17m, and a design speed of 80 km/h.
In front of the Vung Mountain Tunnel. Photo: Deo Ca Group
On this route, the Vung Mountain Tunnel is 2.2 km long, the longest tunnel on the North-South expressway and the 4th largest tunnel in the country after the Hai Van, Deo Ca, and Cu Mong tunnels. When put into operation, the tunnel has a scale of 3 lanes, with a tunnel width of 14 m. The Vung Mountain Tunnel has a total investment capital of about 1,600 billion VND and a construction period of 30 months.
On July 3, 2023, the Vung Mountain Tunnel was officially opened, marking an important milestone for the road construction and progress of the project, laying the foundation for completing the entire Cam Lam – Vinh Hao expressway project before April 30, 2024.
Reinforcing tunnel with NATM construction technology
The Vung Mountain Tunnel in Ninh Thuan province is built with the NATM (New Austrian Tunnelling Method) technology, also known as the “new Austrian-style tunnel reinforcement method”. This technology is highly appreciated by experts for its flexibility and safety when applied to different types of geological conditions, surpassing traditional tunneling methods.
The NATM technology has also been successfully used to construct tunnels through mountains such as Deo Ca, Co Ma, Cu Mong, Hai Van, Thung Thi, and the Quang Ninh seaway tunnel. NATM is a widely used underground construction method, notable for its breakthroughs in shotcrete technology.
The NATM method optimizes the self-supporting ability of the terrain, which is considered one of the most economical and effective techniques in tunnel construction. At the same time, it helps minimize costs for materials, labor, and shortens project timelines.
In particular, NATM is extremely effective in withstanding geological pressure in areas with high earthquake risks. This method has become a major solution for building many road tunnels worldwide.
Bustling traffic, construction equipment in the Vung Mountain Tunnel. Photo: Deo Ca Group
During the tunnel excavation process, the construction unit discovered weak geological conditions that differed from the technical dossier approved by the Ministry of Transport, so they invited experts from the State Inspection Council, Project Management Board 85, and design consulting units to propose appropriate solutions.
On the construction site, the contractor mobilized 1,500 personnel and used more than 500 types of machinery and equipment to serve the project. Among these are many advanced devices imported to serve the construction work, suitable for the specific geological conditions of the project, such as tunnel drilling machines, rotary drilling rigs for hard rock breaking during pile driving, crushing stations, material mixing stations, etc.
In terms of stone materials, the construction contractor actively tested the actual quality of the stone materials obtained from tunnel excavation and roadbed construction in order to classify and effectively use them, transforming them into different types of aggregates for cement, asphalt, and stone base material. As a result, the contractor was able to supply about 80% of the necessary stone materials for the project.
Opening the Vung Mountain Tunnel ahead of schedule in July 2023 facilitates the smooth coordination of personnel, vehicles, and construction materials for the Cam Lam – Vinh Hao expressway without having to detour through public roads, speeding up the project’s completion.
