At 4 a.m. on April 20

As the signal light turned from red to green

social vehicles drove from the former Sixth Ring Road into the East Sixth Ring Road Tunnel

marking the completion and opening to traffic of the East Sixth Ring Road renovation project

in which China Railway 14th Bureau Group participated in the construction

The East Sixth Ring Road renovation project is a key municipal project implementing the "Master Plan of Beijing" and the "Regulatory Detailed Plan for Beijing Municipal Administrative Center". Located in the Beijing Municipal Administrative Center in Tongzhou District, it starts from the Jingha Expressway in the south and extends to Luyuan North Street in the north, with a total length of about 16.3 kilometers. The 7.4-kilometer shield tunnel is the controlling project of the entire line.Using the shield tunneling method to put the Sixth Ring Road underground not only avoids damaging surface rivers, vegetation and buildings, but also restores green space on the surface, "stitching together" urban spaces that had been severed.

Custom-built "Jinghua" shield tunneling machine 

leading the innovative transformation of large-diameter shield tunneling

The tunnel adopts a separated double-tube layout, with 3 lanes in each tube, a design speed of 80 km/h and a maximum depth of 75 meters. It is the deepest underground tunnel in Beijing and the longest shield-tunnel expressway ever built in China. The west-line tunnel undertaken by China Railway 14th Bureau Group has a total length of 7,336 meters, crossing over long distances through dense water-rich sand layers and passing beneath 55 risk sources including railways, subways, highways and rivers. It presents construction difficulties such as an ultra-large diameter, ultra-long distance, ultra-deep overburden and ultra-sensitive environment.

In response to the construction difficulties, the project team custom-built the "Jinghua" shield tunneling machine, which was the largest-diameter shield tunneling machine made in China at the time and the country's first 16-meter-class ultra-large-diameter shield tunneling machine. During construction, the "Jinghua" shield tunneling machine made frequent appearances and attracted worldwide attention, becoming a vivid example of China's large-diameter shield tunneling leading innovation and transformation.

▇ On September 27, 2020, the "Jinghua" shield tunneling machine, the largest-diameter shield tunneling machine made in China, successfully rolled off the production line, and the photo was included in the "Questions and Answers on the Study of Xi Jinping Thought on Socialism with Chinese Characteristics for a New Era".

▇ On May 28, 2021, when summarizing "new breakthroughs in high-end industries" at the General Assembly of the Chinese Academy of Sciences and the Chinese Academy of Engineering and the Tenth National Congress of the China Association for Science and Technology, General Secretary Xi Jinping pointed out that "the largest-diameter shield tunneling machine was successfully launched", and "Jinghua" became a vivid example of China's large-diameter shield tunneling leading innovation and transformation.

▇ From October 21 to 27, 2021, the National "13th Five-Year Plan" Science and Technology Innovation Achievement Exhibition was held at the Beijing Exhibition Center, and General Secretary Xi Jinping visited the exhibition. The "Jinghua" (model) made a brilliant appearance in the "High-Tech Exhibition Area", becoming a typical sample of the continuous deep integration of national advanced manufacturing and scientific and technological innovation that boosts the technological upgrading of manufacturing.

▇ On September 27, 2022, General Secretary Xi Jinping went to the Beijing Exhibition Center to visit the "Forging Ahead in the New Era" themed achievement exhibition. "Jinghua" was honored to be exhibited as a model of a key independently developed product demonstrating the leap in China's scientific and technological level and manufacturing capability.

▇ From May 10 to 14, 2023, the 2023 China Brand Day event was held at the Shanghai World Expo Exhibition and Convention Center. The model of the "Jinghua" shield tunneling machine shared the stage with major national heavy equipment such as the China Space Station, the J-20 "Mighty Dragon" and the "Guohe No. 1", fully demonstrating the strong strength of Chinese brands.

▇ On May 30, 2023, the "Jinghua" shield tunneling machine (model) was permanently collected by the Museum of the Communist Party of China.

▇ In July 2023, the "Jinghua" shield tunneling machine was selected into the list of 100 "Witnesses of the New Era".

Successively overcoming 55 risk sources

setting multiple construction records

Since its launch in May 2021, the "Jinghua" has withstood multiple tests, successively overcoming 11 technical challenges including shield launching under shallow overburden, high-risk hoisting of the shield machine and long-distance crossing of highly dense sand layers. It successfully crossed 55 risk sources such as the Jingha Railway and the Beijing Municipal Administrative Center Comprehensive Transportation Hub, kept ground settlement under millimeter-level control, and set many new construction records for projects of the same type:

• Completed the main structure capping of the launching shaft in 7.5 months.

• Completed factory assembly of the shield tunneling machine in 6.5 months.

• Completed overall assembly and debugging of the shield tunneling machine in 60 days.

• Completed construction of a 110kV temporary substation and successfully energized it in 2.5 months.

• The shield tunneling machine achieved a daily advance of 24 meters and a monthly advance of 542 meters, setting a new monthly advance record for 16-meter-class ultra-large-diameter shield tunneling machines.
  

• Completed disassembly and transportation of the shield tunneling machine in 33 days.

Pioneered ultra-large-diameter simultaneous dual-liquid grouting technology

filling a domestic gap

In R&D and construction application, the "Jinghua" pioneered in China the simultaneous dual-liquid grouting technology for ultra-large-diameter slurry shield tunneling. After three years of exploration and practice and a year and a half of scheme demonstration and testing, the technology was effectively verified in the Beijing East Sixth Ring Road renovation project.

During construction, compared with traditional grout, the grout of the "Jinghua" shortened the consolidation time from 8 hours to 1 hour and could quickly reach effective strength, reinforcing the tunnel and supporting the strata. According to third-party monitoring, the "Jinghua" achieved millimeter-level control of ground settlement, which remained at the millimeter level throughout the crossing of risk sources, ensuring zero disturbance to existing surface buildings from shield construction.

According to expert demonstration by Qian Qihu, academician of the Chinese Academy of Engineering, and other experts, the simultaneous dual-liquid grouting technology of the "Jinghua" has remarkable practical effects and high technological content. It is the first of its kind in China and fills the domestic gap in simultaneous dual-liquid grouting for ultra-large-diameter slurry shield tunnels.

At present, based on the simultaneous dual-liquid grouting technology applied in the Beijing East Sixth Ring Road renovation project, more than 20 construction methods, patents and standardized process flows have been developed.

Party building leadership gathers development synergy

empowering the construction of a world-class benchmark project

Building a "major national project" is inseparable from the leadership of Party building. Since the establishment of the Party branch of the Beijing East Sixth Ring Road project, it has adhered to the principle of "approaching Party building from the perspective of work and approaching work from the perspective of Party building", ensuring that wherever the "Jinghua" tunnels, the Party flag flies and the "Party Member Pioneer Posts" tackle difficulties there, providing strong organizational guarantee and spiritual motivation for project construction, and alsohas won a series of honors:

• Selected as a demonstration project for the Safe Century Quality Project and a science and technology demonstration project by the Ministry of Transport.

• The "1244 Working Method" was selected into the "Cases of 100 Benchmark Party Branches" by the magazine "State-Owned Enterprises" and the first batch of outstanding Party building brands in the highway transportation industry.
  

• Awarded "Advanced Grassroots Party Organization of Central Enterprises" by the State-owned Assets Supervision and Administration Commission of the State Council.

• Awarded the "Locomotive" Trophy by the All-China Federation of Trade Unions.

• Awarded the "Railway Youth May Fourth Medal Collective" by the National Railway Youth League Committee.
  

• Awarded Demonstration Party Branch of China Railway Construction.

• Awarded Youth Civilization Unit of China Railway Construction.

  ……

As an industry benchmark project, the Beijing East Sixth Ring Road project not only set multiple new records in shield tunnel construction, but also created a phenomenal communication effect in the field of engineering communication, forming a unique communication paradigm for major projects.The editorial department of CCTV News Broadcast, Guangming Daily, the Party branch of the News Center of SASAC, and the National Industry Newspaper Association successively visited the Beijing East Sixth Ring Road project for on-site visits through themed Party days, Party building co-construction and other methods.During the entire tunneling period of the "Jinghua" shield tunneling machine, media at all levels reported more than 1,000 articles in total, including more than 240 central-level reports, among which CCTV reported more than 100 times. A total of 14 key documentaries were produced around the project, and programs such as "Innovation in Progress", "Fashion Tech Show", "Amazing China", "Red Imprint" and "Please Come to My Concert" carried out diversified reports. The project also appeared several times on "Focus Interview", especially with a brilliant opening in "The Code of Leading: Shield Tunneling Machines: A Comeback in Tunneling", and appeared in the 2024 Spring Festival Gala and the 2022 "Chinese Dream, Labor Beauty" May 1 special program, among others.

As a key project of Beijing and a landmark project of the Beijing Municipal Administrative Center, the opening of this national-level "Safe Century Quality Demonstration Project" and "Science and Technology Demonstration Project" is an important channel connecting Shunyi, Daxing, Yizhuang, Beijing Capital International Airport and Beijing New Airport, and is of great significance for promoting the coordinated development of transportation in the Beijing-Tianjin-Hebei region, improving the city's transportation service level and building a comprehensive transportation system.