The shield tunneling machine "Macao-Hengqin 1" started drilling on the 2.2-km (1.4-mile) Macao Light Rail Transit extension to Hengqin on July 13, marking the beginning of construction for the first large-diameter subsea shield tunnel connecting Macao and Hengqin.

The extension runs on the viaduct from HE1 Station near Lotus Bridge Station of the Taipa Line in Macao and continues 900 m (984 yd) under the Shizimen Waterway alongside the Lotus Bridge to HE2 Station beneath Hengqin Checkpoint. It will be an important passenger corridor connecting public transportation in Zhuhai and Macao.

Shield tunneling machine "Macao-Hengqin 1" starts drilling [Photo courtesy Zhuhai Daily]

The 900-m (984-yd) tunnel is the first of its kind in Macao to use the shielding technique. However, problems like a weak formation of silt stratification and surface subsidence control for architectures along the Hengqin-Macao border have to be overcome.

As a result, "Macao-Hengqin 1" was customized by the project constructor Nam Kwong Group to operate more efficiently. The 87-m-long (95-yd-long) machine is 7.98 m (8.73 yd) in diameter, which is the largest of its kind in diameter applied in Macao.

Project construction started in March 2021 and is estimated to take more than three years. Upon operation, the extension will bring convenient cross-boundary transportation for people in Hengqin and Macao, as well as lay a solid foundation for Macao's integration into the one-hour living circle within the Guangdong-Hong Kong-Macao Greater Bay Area.