On May 19, the super-large diameter tunnel boring machine (TBM) “Jincheng No.1” successfully completed its breakthrough beneath the Haihe River in Tianjin. This milestone is part of the Tianjin-Weifang High-Speed Railway project, constructed by CRCC, which has now surpassed 5,000 meters of total tunneling progress.
The Tianjin-Weifang High-Speed Railway begins at Binhai Station in Tianjin and connects to Weifang North Station on the Jinan-Qingdao High-Speed Railway. The main line spans 348.9 kilometers, includes 10 stations, and is designed for speeds up to 350 km/h. The Jin-Gu Haihe Tunnel, approximately 6.7 kilometers long, is the sole tunnel along this railway, featuring the largest shield diameter ever constructed beneath the Haihe River.
Tunneling is being carried out using the domestically produced “Jincheng No.1” slurry balance TBM, which boasts a maximum excavation diameter of 13.8 meters. During the river crossing, the TBM passed beneath a 267-meter-wide section of the Haihe River, with a minimum cover of just 17.3 meters below the riverbed and a maximum water depth of 12 meters.
The project faced significant technical challenges due to complex geological conditions, including fractured zones, soft soils, and layers prone to liquefaction. The construction team expertly navigated these difficulties while minimizing environmental impact and ensuring the structural safety of nearby infrastructure, such as the Central Avenue Haihe Tunnel.
To guarantee the safe passage of the TBM under the river, the team conducted thorough geological surveys and environmental assessments and developed comprehensive emergency protocols based on test section data. During this critical phase, engineers employed innovative techniques such as shield muck treatment technology and a dual-liquid synchronous grouting system. Real-time automated monitoring tracked ground settlement throughout the operation, enabling the team to safely cross the river without causing any disturbance to the existing Central Avenue Haihe Tunnel above.
As a vital segment of China’s high-speed rail network, this line forms part of both the Beijing-Shanghai and Coastal Corridors. Once completed, it will greatly enhance connectivity within the Bohai Economic Rim, support the integrated development of the Beijing-Tianjin-Hebei region, and promote the growth of the Shandong Peninsula urban cluster.
