Proposal for nearly 1,300 billion VND to invest in completing and increasing the exploitation capacity of Cu Mong tunnel

The Cu Mong tunnel project is proposed to invest in completing the remaining tunnel and the two-way access roads, ensuring effective exploitation in sync with the 4-lane North-South expressway in the East.

Existing risk of overload

Project Management Board 85 has just submitted a report to the Ministry of Construction on the investment policy for the Cu Mong tunnel project and the access roads at both ends of the tunnel on the Eastern North-South expressway.

Inside Cu Mong tunnel.

The content of the report said that the North-South expressway project, Quy Nhon - Chi Thanh section, has a route going through Cu Mong tunnel.

According to the plan, the route will be completed and put into operation on the entire route with a scale of 4 lanes in the phased phase, the roadbed width is 17.5m. The route of the Quy Nhon - Chi Thanh project is intermittent, connecting directly with Cu Mong tunnel (from Km 19+800 - Km 24+900). In which, Cu Mong tunnel is 2.6 km long and is being exploited with a scale of 2 lanes.

The location of the expressway section through Cu Mong tunnel is considered one of the bottlenecks of the entire expressway, affecting the exploitation capacity, operational capacity and efficiency of the Eastern North-South expressway.

According to the survey data of the consultant for the Quy Nhon - Chi Thanh project conducted from February 21-27, 2022 on National Highway 1 in Xuan Loc commune, Song Cau town, the flow rate is 13,595 PCU/day and night. In Xuan Phuong commune, Song Cau town, the flow rate is 20,594 PCU/day and night.

The growth rate of traffic on National Highway 1 before the Covid-19 pandemic was around 7-10%. The forecast traffic volume on National Highway 1 (including the expressway) by 2025 is around 25,000-27,000 PCU/day and night. This volume will lead to the possibility of overloading the 2-lane scale through the Cu Mong tunnel area.

In the step of preparing the feasibility study report for the Quy Nhon - Chi Thanh section, Project Management Board 85 reviewed and studied the addition of the Cu Mong tunnel completion item to the Quy Nhon - Chi Thanh section component project and reported to the competent authority.

The expansion of Cu Mong tunnel will help maximize the efficiency of the regional transportation system, reduce the load on National Highway 1, enhance connectivity between economic zones, industrial parks and seaports, and promote socio-economic development for Binh Dinh, Phu Yen and neighboring areas.

"In documents, meeting notices and announcements of site inspection results, the Ministry of Transport (now the Ministry of Construction) also assessed that the investment in completing the Cu Mong tunnel with a scale of 4 lanes is necessary," informed Project Management Board 85.

Completing the remaining tunnel in the immediate future

Regarding the investment plan, Project Management Board 85 said that Cu Mong tunnel is currently operating in two directions on the western tunnel with a speed limit of 60 km/h.

The left tunnel with a length of more than 2,572m (from Km2+002.81 - Km4+575.18 - Cu Mong tunnel project route), tunnel width of 9.75m has been built but not completed (without cement concrete road surface and electrical equipment, lighting, ventilation,....).

To ensure the synchronous exploitation of the North-South expressway according to the scale of phase 1 with 4 lanes, the project management unit proposed to continue investing in completing the second tunnel with the following items: Construction of the remaining tunnel shell, road surface inside and outside the tunnel, equipment system serving operation and exploitation (ventilation, lighting, fire prevention and fighting...).

The Cu Mong tunnel approach road is being expanded to a scale of 4 lanes; the bridge project will complete 2 bridges to a scale of 6 lanes.

With the above plan, the total investment is expected to be nearly 1,300 billion VND, including: construction cost of nearly 876 billion VND; equipment cost of more than 179 billion VND; project management cost, construction investment consultancy and other costs of more than 126 billion VND; contingency cost of more than 188 billion VND.

If approved, the project is expected to be implemented from 2025 and completed and put into use in 2027.

In the investment phase of Cu Mong tunnel according to the planning scale, 3 options were considered by Project Management Board 85.

Option 1: Build 1 more tunnel to the left of the 2 existing tunnels, exploit the new tunnel with 3 lanes, each lane is 3.5m wide, with a design speed of 80 km/h. With 2 existing tunnels, exploit each tunnel with 2 lanes.

Option 2: Build a new tunnel to the right of the 2 existing tunnels, across the valley, on the mountain opposite the existing mountain, far away from the 2 existing tunnels, exploit the new tunnel with a scale of 3 completed lanes (design speed 100 km/h). With 2 existing tunnels, exploit each tunnel with 2 lanes.

Option 3: Dig and widen both tunnels, ensuring operation with a scale of 3 lanes per tunnel with a design speed of 80km/h. Dig and widen the left tunnel first, construct the support system, complete the left tunnel, to ensure traffic when constructing the right tunnel.

Through comparing the options in the completion phase with a scale of 6 lanes in terms of technical economics, according to the assessment, option 3 cannot take advantage of the constructed tunnel tubes, almost having to demolish the existing tunnel, rebuild the entire support structure system, tunnel shell...

"Options 1 and 2 make full use of the two existing tunnels, contributing to putting the project into use soon.

With option 2, the new tunnel can be exploited at a speed of 100 km/h. However, in the tunnel scope, the exploitation speed at 100 km/h and 80 km/h, the time difference through the tunnel is insignificant (

Meanwhile, option 2 has many limitations such as: high construction costs, the option to build a new tunnel on the left side of the mountain is far from the existing tunnel, so it is necessary to add an additional shelter. Therefore, option 1 is considered suitable with low construction costs, limiting expansion and land occupation", Project Management Board 85 assessed.

Source: https://www.baogiaothong.vn/de-xuat-gan-1300-ty-dong-dau-tu-hoan-thien-tang-nang-luc-khai-thac-ham-cu-mong-192250328123058527.htm