Tunneling through mountains, bridging across rivers
The Chi Thanh – Van Phong expressway passing through Phu Yen province is one of the 12 component projects of the North-South East expressway Phase 2 (2021-2025). The project started on 1/1/2023 and is expected to be substantially completed by 2025. After more than a year of construction, the entire Chi Thanh – Van Phong expressway project has achieved more than 28% of the contract value and is about 1.8% behind schedule. The Tuy An tunnel on this expressway is particularly behind schedule by 2 months.
This is due to weak geological conditions encountered in the Tuy An tunnel. When the tunnel was excavated to a depth of 35m, the construction unit discovered that the weathered rock had turned into soil and the geological conditions were unstable, significantly different from the initial design specifications. Therefore, the contractor had to reinforce the tunnel to prevent landslides and had to adjust the construction schedule accordingly.
Unlike the conventional method of tunnel construction, which involves excavation followed by concrete spraying, the contractor had to drill and install steel pipes to pump cement mortar and additives into the tunnel arch to prevent landslides. This process has taken more time for tunnel excavation and reinforcement, with only 1m completed per day compared to the previous completion rate of 6m per day.
The Tuy An tunnel is a crucial part that affects the progress of the entire project. Photo: Deo Ca Group
In the Tuy An tunnel project, the main contractor has deployed 3 continuous working shifts. Specifically, shift 1 is responsible for reinforcing the tunnel roof, including excavation and reinforcement of the beam frame, installation of cladding panels, and backfilling of soil; while shift 2 and 3, corresponding to the left and right tunnels, have completed excavation and reinforcement of over 300m out of the total length of 772m in the project.
The Tuy An tunnel project started in July 2023, with the construction of a 1km-long two-lane tunnel with 2 emergency stopping lanes and a design speed of approximately 60km/h. The first phase will open the right tunnel from Van Phong to Tuy Hoa. The remaining tunnel will be used as an emergency tunnel.
The most notable project on this expressway, besides the Tuy An tunnel, is the Da Rang River Bridge (Tuy Hoa City, 2.2km long). The Da Rang bridge is one of the 48 main bridges on the North-South expressway through Phu Yen province.
The construction process on the Da Rang River Bridge site is bustling with over 200 workers, engineers, and numerous machinery and equipment… With the current progress, the contractor aims to complete the Da Rang River Bridge 6 months ahead of schedule.
A view of the Da Rang River Bridge from above. Photo: To Quyen
Impressive machinery on the construction site
Currently, on the entire Chi Thanh – Van Phong expressway, the contractors have deployed 45 construction teams and 537 pieces of equipment with over 1,300 personnel, focusing on the construction of bridges, culverts, tunnels… and essentially meeting the requirements.
Mr. Truong Cong Dat – Deputy Director of the Contract Package Management Board, said that during the days when engineers and workers were on Tet holiday, all motorcycles and equipment were also given rest and “check-ups”, maintenance, and thorough inspections to ensure that the motorcycles and equipment were in the best technical condition, increasing operational efficiency after Tet.
Additional motorcycles and equipment are mobilized to accelerate the construction progress after Tet. Photo: Deo Ca Group
“From the early days of undertaking this contract package until now, the contractors have invested in a range of advanced motorcycles and equipment for construction purposes. The machinery and equipment are regularly maintained to suit the weather conditions and the operating frequency at the construction site. In addition, the contractor has organized training for the management team and drivers and operators to improve their management skills and machine operation, with the goal of optimizing operating capacity, ensuring the quality and lifespan of motorcycles, equipment, and achieving the most efficient implementation of the contract package,” Mr. Truong Cong Dat shared.
The Chi Thanh – Van Phong expressway passing through Phu Yen province connects to the Quy Nhon – Chi Thanh expressway at the starting point and to National Highway 1 at Deo Ca tunnel. The expressway is over 48km long, with a total investment of over 10,700 billion VND.
To match the resource balancing capability and ensure investment efficiency, in the 2021 – 2025 phase, the project will be invested in a staggered manner with 4 lanes, a road foundation width of 17m; and a design speed of 80km/h.
The project mainly runs in the westward direction of National Highway 1 (about 15-20km on average away from National Highway 1). From the intersection with the road connecting to Chi Thanh town, the route runs parallel and about 0.5 – 3.5km away from National Highway 1, passing through the communes of Chi Thanh, An Hiep, intersecting with DT643 in An My commune, and then goes through the plain area of communes: An Chan, An Phu, Hoa Kien, Hoa Tri. At this point, the route is adjusted compared to previous studies to avoid encroaching on the range of the power lines or military land. From there, the route intersects with QL25.
From QL25, the route crosses the Da Rang River, continues through Hoa Xuan Tay commune towards the downstream of Han hydropower dam, and connects to the Deo Ca tunnel and Co Ma tunnel at the project’s endpoint.
