The shield section of the Sanzao Tunnel of Zhuhai Airport Urban Rail Transit Phase II was broken through July 27, a year ahead of schedule.

The Sanzao Tunnel runs 4.1 km (2.5 miles) westward along Airport Road in Jinwan District. It cuts through the hilly area of Xiajiaoju on east-central Sanzao Island and is divided into shield, mine, and cut-and-cover sections.

The 2.2-km (1.4-mile) shield section is a double-hole single-lane structure near the coast. This is where silt stratification can cause gushing and instability during construction, according to Chu Zhijian, China Railway 16th Bureau Group deputy manager of the section.

In addition, ground surface subsidence must be meticulously controlled during evacuation due to the large traffic flow on Airport Road. Other challenges include pipelines, cables, overpasses, three-hole box culverts, and ancestral halls.

Breakthrough celebration banners [Photo by Zhong Fan / Guanhai App]

Work on the shield session commenced July 16, 2019. The project team adjusted the plan from use of one shield machine to two devices better-suited to the geological environment.

The Zhuhai Airport Urban Rail Transit Phase II will reach Chimelong International Ocean Resort in Hengqin New Area. It will pass through Big Hengqin Mt to Jingwan Station, over West Huandao Road, and merge into the upcoming highway-railway Jinhai Avenue Bridge. 

Hezhou South Station will be set up in South Hezhou Reclamation Area after crossing the Modaomen Waterway. Sanzao East Station will be built at the Airport Road and County Highway X590 intersection after crossing the Baiteng River. The terminus station at Zhuhai (Jinwan) Airport will be underground.

In all, the 22.8-km (14.2-mile) rail line requires three bridges spanning 11.88 km (7.38 miles) and four tunnels with a combined length of 10.07 km (6.26 miles). The project is expected to be completed in early 2023.

An extension of the Guangzhou-Zhuhai Intercity MRT, the 39.48-km (24.5-mile) Zhuhai Airport Urban Rail Transit is a significant part of the Guangdong-Hong Kong-Macro transport network. It will cut travel time between Gongbei and Zhuhai (Jinwan) Airport to half an hour.

The first phase spans 16.86 km (10.48 miles) from Intercity MRT Zhuhai Station in Gongbei to Hengqin Chimelong Station in Hengqin New Area. Although it is eligible for operation, the official opening date of the section is yet to be determined.