On August 20, good news came from the Hebei section of the Beijing Rail Transit Line 22 project: since the first shield machine "Sanhe" was launched on July 26, 2023, after more than a year of continuous tunneling, the underground shield-driven section of the Hebei section has accumulated 15 kilometers (9,375 rings) of tunneling, completing 50% of the total shield construction volume—the shield tunneling mileage of the Hebei section of Line 22 has successfully passed the halfway mark.

On August 20, the construction site of the shield-driven section from Gaolou Station to Qixinzhuang Station of Beijing Rail Transit Line 22, located in Sanhe City.

As a landmark line of the "rail-connected Beijing-Tianjin-Hebei" initiative, Beijing Rail Transit Line 22 is the first inter-provincial urban rail transit line between Beijing and Hebei, with a total length of approximately 81.2 kilometers, divided into the Beijing section and the Hebei section. The Hebei section has a total length of approximately 30 kilometers and comprises 5 stations and 6 intervals, namely Yanjiao Station, Shenwei Dajie Station, Chaobai Dajie Station, Gaolou Station, and Qixinzhuang Station.

At around 11 a.m. on August 20, in the left-line shield-driven interval from Chaobai Dajie Station to Gaolou Station, the "Fenjin" shield machine—with an excavation diameter of 8.29 meters, a total length of about 109 meters, and a total weight of about 1,400 tons—advanced slowly forward like a giant dragon. At present, the "Fenjin" has tunneled 2,104 meters (1,315 rings) and has safely and smoothly completed the construction task of passing beneath the Xingfu Canal and the Beijing-Qinhuangdao Expressway.

According to reports, the shield machine is equipped with an intelligent tunneling management system, a muck metering system, an automatic shield tail clearance measurement system, and others, which can effectively improve the automation and intelligence level of the shield machine and achieve refined management of shield tunneling construction.

In addition, the project technical team is also committed to technological innovation and encourages all staff to innovate and create value. Before the "Fenjin" officially started the tunneling task of the Chaobai Dajie-Gaolou shield-driven interval (the shield-driven interval from Chaobai Dajie Station to Gaolou Station), the confined space made both shield launching and segment transport difficult—the minimum spacing between the base slab frame columns and the side walls of Chaobai Dajie Station is only 4.65 meters, and the conventional 5.5-meter-wide trolley could not "exercise its abilities" here.

The existing station structure cannot be changed, and split launching is also not feasible. The project technical team changed its approach, starting with the modification of existing trolleys and equipment and adopting "unconventional" tunneling methods to solve the shield launching problem.

During the first 65 rings of tunneling, the project technical team first modified the 5.5-meter-wide trolley to a width of 4.5 meters, achieving "freedom" of entry and exit while ensuring functionality. At the same time, they designed a new type of automatic reversible segment turning machine that allows segments to be transported synchronously with the battery locomotive. It can not only steadily "grip" the segments lowered into the shaft laterally on the established track, but also, after a 90-degree horizontal turn, transport the segments vertically to the "destination," providing "supply" for the assemblers.

This technology of "variable-width trolley + narrow-body rear supporting equipment formation + segment turning trolley" effectively breaks through the structural space limitations of the existing launching station and greatly improves construction efficiency!

To ensure smooth shield tunneling, the project team has also continuously improved the construction plan and carried out standardized management of the site. Before the start of important work points, they conduct "simulation drills," implement special incentives for important milestones, strengthen "backpack management" and quality acceptance process control at the construction site, and carry out refined and grid-based management of project quality, comprehensively ensuring project quality.

After the completion of Beijing Rail Transit Line 22, Sanhe Yanjiao will be connected to the Beijing urban rail transit network. The fastest travel time from Sanhe Yanjiao to the Beijing Municipal Administrative Center will be 9 minutes, and the shortest time to the Beijing CBD area (Dongdaqiao Station) will be about 32 minutes. The central urban area of Beijing, the Beijing Municipal Administrative Center, Sanhe City in Langfang, and Pinggu District in Beijing will achieve rapid rail transit interconnection. The line is of great significance for promoting the integrated high-quality development of Beijing's Tongzhou District and the three northern counties of Langfang, driving regional economic development, and improving people's livelihoods.