Bangabandhu Tunnel: A new addition to country’s engineering study

The construction of a tunnel under the Karnaphuli River is a first for South Asia. Under the project, two tubes were excavated under the river and subsequently converted into a road. While the contractor was China Communications Construction Company Limited (CCCC), six consulting firms collectively participated in the project under the Bangladesh Bridges Authority. Senior Site Supervision Engineer SM Mostafijur Rahman, a key figure in the main consulting firm SMAC, has been involved in the project since its inception.

Mostafizur, hailing from Chuadanga, completed his B.Sc. Honours degree in the Civil Engineering Department at Rajshahi University of Engineering and Technology (Ruet) in 2007. He then joined SMAC in 2008. Prior to his involvement in the Bangabandhu Tunnel project, he had worked on the Mouchak-Moghbazar flyover project. He shared his experience of working for six years beneath the river during an interview with The Business Standard.

Tell us about your work experience on South Asia's first tunnel project

In addition to the unique aspect of constructing an under-river tunnel, another noteworthy feature of this project is the use of the FIDIC Silver Book contract. Unlike the typical FIDIC Red Book Agreement used in Bangladesh for projects, the Silver Book contract allows for greater flexibility in project execution. In the Silver Book contract, not everything is predetermined, including the project's design, and work is carried out based on project requirements.

The soft soil beneath the river in Bangladesh posed a significant challenge for this project. Due to the nature of the soil, it was essential to work with high speed and precision. The risk was heightened because if an accident occurred during the tunnelling process, it could have led to the entire project's cancellation, potentially leaving the tunnel boring machine (TBM) trapped underground. Despite these challenges, the project was completed successfully.

Which part of the project did you find most challenging?

Tunnels are typically excavated on hard ground, but we encountered difficulties due to the soft soil in this area. The tunnel boring machine was coming up after completing only about half of the work in the north tube. The tunnel is formed by placing concrete segments in the tube to create rings. These segments are manufactured in China, where the winter temperatures can drop below freezing. This created some challenges because these segments require normal temperatures to function properly. Since this is the first tunnel construction project in Bangladesh, the decision was made to produce the segments in China to avoid the risk of working with them in Bangladesh.

Additionally, there were challenges during the construction of cross passages. However, we successfully stabilised the soil by converting it into ice, which made it unnecessary to wear safety equipment in that area.

The success of this project holds significant importance for our infrastructure development initiatives. Other projects, such as underground developments and Bus Rapid Transit-Metro Rail Transit projects, were dependent on the outcome of this tunnel project. If this tunnel project were to fail, it could deter international financiers, contractors, or consultants from participating in larger projects due to the associated risks.

What kind of role do you think the work experience on the tunnel project will have in your career?

The experience gained from working on the project will serve as a valuable skill for any future underground work. I believe it will not only benefit me as an individual but also contribute to the advancement of engineering as a whole. In our curriculum, we were traditionally taught about flyovers, bridges, and culverts in the highway and transportation sectors. However, due to the successful completion of the tunnel project in our country, I anticipate that it will be incorporated into the curriculum in the future. Overall, it has the potential to elevate the engineering sector of the country to new heights.

Shahiduzzaman Saju, an engineer who was part of the tunnel project, has already joined a Sydney-based firm as a tunnel engineer. This demonstrates the recognition of our work experience and skills.

How do you feel about working on the project?

Certainly, it's a matter of great pride. I've entered the tunnel at least 500 times. During the construction phase, when the slabs had not been installed, I would go down several times a day. I have worked at both ends of the tunnel and inside it. I am truly delighted to have been a part of this historic project.

Of course, it is a matter of pride. I have been inside the tunnel at least 500 times. When slabs had not been set in the tunnel, I went there several times a day. I have worked on both ends of the tunnel and inside. I am glad to be a partner in this historical project.