On the morning of January 13, within the construction enclosure along National Highway 107 in Bao'an District, Shenzhen, the main structure of Zhongwu Station on Metro Line 12 was successfully capped ahead of schedule as the concrete pouring for the 18th roof slab section was completed. This is also the first station on the line to be capped in 2021. To date, 19 stations along the entire Line 12 have been capped, and construction progress continues to lead Shenzhen's Phase IV rail transit projects.

Line 12 runs from Zuopaotai in Shekou, Nanshan, to Haishang Tianyuan East

Shenzhen Metro Line 12 is one of the important lines of Shenzhen's Phase IV rail transit projects and is constructed by PowerChina. Line 12 starts from Zuopaotai in Shekou, Nanshan, and ends at Haishang Tianyuan East, with a total length of about 40 kilometers. It is built underground and has 33 stations, including 18 interchange stations, serving as a backbone line running through the western development axis of Shenzhen. Construction began in January 2018, and trial operation is expected in 2022.

According to Fan Heyu, owner's representative of the Civil Works Section V of Line 12 for Shenzhen Metro Construction Group, Zhongwu Station is located along the Zhongwu-Huangtian section of National Highway 107 and is an underground two-level, two-island, three-track platform station. The station has a total length of 596.7 meters, and the clear width of the standard section structure ranges from 30.3 to 32.454 meters. It is constructed using the semi-covered cut-and-cover method. The designed earthwork excavation is 340,000 cubic meters, the main structure requires 14,886 tons of rebar installation and 64,763 cubic meters of concrete pouring.

25 pieces of equipment deployed for station earthwork excavation, with over 400 truckloads of soil removed daily

Fan Heyu said, “Zhongwu Station is one of the most difficult stations on the entire line, and its difficulty lies in traffic diversion.” National Highway 107, where Zhongwu Station is located, has 12 lanes in both directions and is extremely busy, with traffic volume reaching 250 vehicles per minute in both directions during peak hours and 300,000 vehicles per day, making it one of the 10 busiest highways in the country. Therefore, National Highway 107 cannot be fully closed. With the guidance and assistance of the Municipal Rail Transit Office, the Bao'an Brigade of Shenzhen Traffic Police and other units, Shenzhen Metro Group, together with PowerChina and the section project department, ultimately determined to carry out traffic diversion in three phases. Resolving this traffic diversion challenge laid a solid foundation for subsequent work.

“Another challenge at Zhongwu Station is the severely limited working space.” It is understood that due to geographical constraints, the narrowest point of the road within the Zhongwu Station site is less than 4 meters, and the widest point is only 8 meters, which significantly affects the frequent entry and exit of large machinery, soil removal and material delivery. Earthwork excavation and steel support installation come first, followed by main structure rebar installation and concrete pouring. The sequential processes and overlapping operations constantly test the organization capabilities of the construction site.

According to reports, “during the construction of the station's main structure, the project adopted staggered working hours to solve the problem of limited space.” It is understood that during peak periods, the project deployed 25 pieces of equipment, including large and small excavators, long-arm excavators, hydraulic grabs and electric grabs, for earthwork excavation, removing over 400 truckloads of soil per day.

19 stations on Line 12 have been capped, with the station main structure completion rate at 72%

The reporter learned that at present, 19 stations along the entire Shenzhen Metro Line 12 have been capped, with the station main structure completion rate at 72%. A total of 45 shield machines have been launched, of which 25 shield tunneling sections have been successfully completed, with the shield tunneling section completion rate at 81%. In addition, the cumulative completion of initial support for mined tunnel excavation along the entire line has reached 88%, and the main structure construction of the Chiwan Depot and Airport East Vehicle Depot is being stepped up.

It is expected that in 2021, the entire line will achieve the goals of full tunnel breakthrough and all stations being capped, and will fully enter the post-station construction stage.