On October 7, as the shield machine's cutterhead broke through the wall, the Bangabandhu Tunnel project undertaken by a Chinese company successfully achieved a double-line breakthrough. It is reported that this is the first underwater tunnel in South Asia and also the first large-diameter underwater shield tunnel implemented by China overseas.

The Bangabandhu Tunnel project is located at the mouth of the Karnaphuli River in Chittagong, connecting the east and west banks of the Karnaphuli River via an underwater tunnel. The route has a total length of 9.3 kilometers, a design speed of 80 kilometers per hour, and two tubes with four lanes. The shield tunnel section is 2,450 meters long, with a tunnel diameter of 11.8 meters. The project uses a slurry balance shield machine independently developed and manufactured by a Chinese enterprise. The cutterhead has a diameter of 12.12 meters, the machine is 94 meters long, and its total weight exceeds 2,200 tons. During the excavation of the left-line tunnel, the project department overcame technical challenges such as shield launching and receiving in water-rich silty fine sand strata, shield attitude control in strata that are soft at the top and hard at the bottom, and shield excavation control in iron-plate sand strata. Before the launch of the right-line tunnel, based on the construction experience accumulated from the left-line tunnel, the shield machine's cutterhead was upgraded and modified, achieving "zero cutter replacement and zero tail brush replacement" during excavation.

The Bangabandhu Tunnel project is the first underwater tunnel in South Asia and the first large-diameter underwater shield tunnel undertaken overseas by a Chinese enterprise, adopting Chinese standards for design, Chinese equipment for construction, and Chinese enterprise management. As an important part of the Bangladesh-China-India-Myanmar Economic Corridor, the completion of the project will not only greatly improve traffic conditions in Chittagong and drive regional economic development in Bangladesh, but also play an important role in improving the Asian highway network, promoting connectivity between Bangladesh and neighboring countries, and advancing Bangladesh's international development.