Longest Tunnel on North-South Highway: 300 Workers, Unique Method, Projected to Finish Ahead of Schedule

Tunnel 3 belongs to Quang Ngai - Hoai Nhon Expressway project, with the length of 3,200m. Upon its completion, it will become the third longest mountain pass tunnel in Vietnam, after Hai Van and Deo Ca tunnels.

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The Quang Ngai – Hoai Nhon project is the section with the largest total investment on the North – South Expressway at VND 20,400 billion, far ahead of the second-placed project, Hau Giang – Ca Mau (VND 17,500 billion). The route has 3 tunnels: Tunnel 1 is 610 m long, Tunnel 2 is 698 m long, and Tunnel 3 is 3,200 m long.

With this length, Tunnel 3 is the largest tunnel newly built on the North – South Expressway, connecting the two provinces of Quang Ngai and Binh Dinh. Upon completion, Tunnel 3 will become the third longest tunnel in the country, after the Hai Van Tunnel and the Deo Ca Pass Tunnel.

The contractor, Deo Ca Group, has mobilized 300 people, worked 24/7, and introduced a special construction method using 6 tunnel construction fronts instead of 4, using water recirculation to save 95% of the construction water. Thanks to the improvement of the tunnel construction method, increasing the number of drilling and excavation steps, and shortening the excavation cycle of a single tunnel face, the tunnel excavation progress has been significantly increased.

The tunnel boring is carried out cautiously. To date, the left tunnel tube has reached 828/3,200m, and the right tunnel tube has reached nearly 889/3,200m.

Previously, Tunnel 1 and Tunnel 2 were drilled and completed ahead of schedule by several months. Specifically, Tunnel 1 was completed 3 months early, and Tunnel 2 exceeded the schedule by nearly 5 months. Subsequently, the general contractor, Deo Ca Group, used these two tunnels as service roads to transport materials, helping to accelerate the construction progress of Tunnel 3.

According to the plan, Tunnel 3 will be completed after 42 months of construction, but the contractor is making efforts to complete this special-grade road tunnel ahead of schedule. The tunnel is expected to be bored through in June 2025 to connect the Quang Ngai – Hoai Nhon Expressway.

Normally, contractors would utilize the excavated soil and rock as construction materials. However, the geological conditions of Tunnel 3 are different from the initial design. This source of soil and rock cannot be utilized. Therefore, Deo Ca Group had to take the initiative to propose a plan to purchase materials from commercial mines while waiting for the design adjustment procedures, which took a long time.

The Quang Ngai – Hoai Nhon Expressway is over 88 km long. The project has a starting point connecting to the Da Nang – Quang Ngai Expressway and an ending point intersecting with Provincial Road 629, connecting to the Hoai Nhon – Quy Nhon Expressway.

Currently, the Quang Ngai – Hoai Nhon Expressway project is being constructed in 3 shifts. The entire Quang Ngai – Hoai Nhon Expressway has deployed 45 construction fronts, mobilizing nearly 3,400 people and over 1,300 machines and equipment to the site.

The Quang Ngai – Hoai Nhon Expressway is invested by Project Management Board 2 (Ministry of Transport). The project started construction on January 1, 2023, and is expected to be completed in 2026.

SOURCEcafef
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