A tunneling shield has been driven a quarter of the way under the Maliuzhou Waterway to create by mid-2023 a fourth roadway -- after the Hengqin and Second Hengqin bridges and Maliuzhou Tunnel -- from mainland Zhuhai to Hengqin Island.

One of the largest shield tunneling machines in China (15.7 m (17.2 yd) in diameter) is moving at 10 m (11 yd) per day toward an entrance near the Zhuhai International Convention & Exhibition Center. About 230 m (252 yd) of the 940-m (1,028-yd) shield segment has been completed.

Shizimen Tunnel under construction [Photo by Zeng Yao / Zhuhai Daily]

Working wells and link lines at both ends of the north-south tunnel are about 80 percent completed, while the main structure for the Fourth Huizhan Road link line in Shizimen has been finished. Pipeline and road restoration is underway.

Electromechanical installations and finishing touches will be done in 2022 to ensure opening in mid-2023, according to Wu Zheng of Huafa Group, the contractor.

Construction commenced in October 2018 at a cost of 2.7 billion yuan ($419 million) to relieve traffic pressure on the Hengqin Bridge to the west. Spanning 2.8 km (1.7 miles), the tunnel will have four lanes with a designed speed of 40 kmph (25 mph).

Once open, the tunnel will shorten travel time between Hengqin Financial Island and Shizimen Central Business District to about two minutes, further boosting growth of the Guangdong-Macao In-Depth Cooperation Zone.

At this time yet a fifth connection is under construction. The first highway-railway structure in the Pearl River estuary, the Jinhai Avenue Bridge is 11.2 km (7 miles) long from southern Hengqin Island to East Airport Road (S727) in Jinwan District. Although the Honghe Bridge crosses over Hengqin's Mangzhou Wetland Park it does not have an interchange on that remote tip of island.