Today (29th), the super-large diameter shield machine "Jiaoping No. 1," jointly developed by China Railway 11th Bureau Group and China Railway Construction Heavy Industry, rolled off the production line in Changsha. The shield machine has a total length of approximately 110 meters, a total weight of about 3,500 tons, and an installed power of 10,000 kilowatts. It possesses the integrated continuous operation capability of "cutting—mucking—lining—grouting," and is currently the world's largest diameter earth pressure balance shield machine for high-speed rail tunnels. In the field of shield tunneling, shield machines are divided into two types: earth pressure balance and slurry balance, primarily based on the applicable ground conditions and working environments. Generally, slurry balance shields are used for river or sea crossings, while earth pressure balance shields are more commonly used in soft rock, urban, and other areas.
During the development of "Jiaoping No. 1," multiple specialized designs were implemented. For instance, the Mangshan Tunnel features large areas of calcareous cemented layers and boulders. The construction team spent two months creating China's first super-large diameter shield cutterhead adapted for soft-hard composite cemented strata. This cutterhead adopts an 8-main-spoke plus 8-panel composite structure with an opening ratio of 46%, equipped with a combination of "disc cutters + ripper teeth + cutting knives," including 61 19-inch single-disc cutters, 14 wear-resistant ripper teeth, and 104 toothed wide cutting knives, achieving full coverage for special strata such as soft soil and cemented layers. The cutterhead surface is covered with chromium carbide composite wear-resistant plates, enhancing wear resistance by 40%. Additionally, the cutterhead is arranged with 20 muck conditioning injection ports, working in conjunction with active mixing bars, a central mixer, and a high-pressure flushing system to effectively prevent clay clogging.
In terms of "software," "Jiaoping No. 1" is equipped with a multi-layered composite grouting system, a simultaneous thrust and segment assembly system, an air pressure-assisted excavation system, and a shield AI intelligent control platform. This allows for the real-time collection of massive amounts of excavation data, enabling automatic monitoring, early warning, regulation, and intelligent fault diagnosis, driving the upgrade of shield construction towards intelligence. According to Chen Jian, project manager of the Mangshan Tunnel on the Jiaozuo-Pingdingshan Railway for China Railway 11th Bureau Group, after leaving the factory, "Jiaoping No. 1" will be disassembled into hundreds of components and transported to the construction site via specialized transport methods, with formal launch and excavation expected by the end of July.