Zhengzhou Tunnel Boring Machine: China's Latest Innovation

The latest advance in China’s tunnel digging arsenal

A 410-foot-long, 5,000-tonne Tunnel Boring Machine (TBM) has emerged from the factory in central China’s Zhengzhou. The machine onrails to increase efficiency and capability in building intricate underwater and urban tunnels. This TBM, the latest in China’s expanding arsenal of tunnel-boring equipment, is designed to tackle the complexities of high-pressure environments and steep slopes.

Stepping up the Game for Urban and Underground Structures

A country with a rapidly urbanising economy, China is under immense pressure to keep up with the demand for infrastructure development. Cities like Beijing, Shanghai, and Guangzhou are expanding rapidly and filled with people. China is racing to build and connect its sprawling cities with efficient, safe, and sustainable transportation solutions. Two of the country’s most prominent railway projects are the Chengdu-Chongqing High-Speed Railway and the Shanghai City Underground Line. The former is a 391-kilometer-long high-speed rail line that connects Chengdu and Chongqing, while the latter spans 1,200 kilometers of urban tunnels under Shanghai. The rising urban population, the need for efficient and safe transportation systems, and the rapid urbanization of cities have all contributed to the increased demand for TBMs in China. TBM is used to bore tunnels for subways, sewers, and other underground infrastructure. The demand for TBMs has increased in recent years as more cities have turned to underground construction to meet the growing demand for transportation infrastructure and to alleviate traffic congestion above ground. There has also been an increase in the number of infrastructure projects in China, such as the construction of sewers and subways.

Serving the full face

The TBM's cutterhead is its key innovation. Designed to work with constant pressure, it allows workers to replace cutters while keeping the pressure inside the excavation chamber steady. This full-face cutterhead works in high-pressure environments up to 8 bars. The cutterhead's ability to operate in high-pressure environments is a significant advance in tunnel boring technology. The cutterhead's constant pressure system keeps the pressure inside the excavation chamber steady while allowing workers to replace cutters. This helps reduce work stoppages and makes maintenance safer.

A cleaner, tougher tunnel

The muck removal system is another critical aspect of the TBM's design. It employs a screw conveyor that pushes the rock straight out, moving the crushing process to an area outside the machine. This design has several benefits. It reduces the risk of blockages and helps maintain a consistent flow of material. The excavator is not affected by the pressure, making it easier to transport and remove rock. The conveyor system also helps to reduce the amount of material that needs to be handled and transported, making the process more efficient. A hydraulic propulsion system and large diameter give this TBM its versatility. The hydraulic propulsion system allows the machine to navigate curves and steep slopes. The large diameter gives the machine a wide working area and allows it to handle steep slopes and curves.

Built for the Long Haul

The machine’s design emphasizes durability and adaptability, crucial in navigating China’s complex geological landscape and urban settings. With a diameter of 54.7 feet and a weight of 5,000 tonnes, the TBM can tackle steep slopes and sharp curves. The propelling system uses hydraulic supports to assist the machine as it moves through curves. This design helps the machine adjust to the terrain and maintain stability while tunneling.

For those who need to know

• Hydraulic propulsion system: This system allows for easy navigation of curves and slopes.
• Wide working area: The machine's large diameter gives it a wide working area, making it easier to handle steep slopes and sharp curves.
• Effective muck removal: The screw conveyor pushes the rock straight out and the crushing happens outside the machine, not inside the chamber. This helps to prevent blockages and maintain a consistent flow of material.
• Constant pressure cutterhead: The machine uses a full face constant pressure cutter head which lets workers replace cutters while keeping pressure steady inside the excavation chamber. This helps reduce work stoppages and makes maintenance safer.
• High-pressure capability: The system works in high-pressure environments up to 8 bars.

China continues to advance its tunnelling infrastructure

The introduction of this TBM is the latest step in China's ongoing work on large shield machines for tough tunnel projects. China has made significant investments in tunnel boring technology, and this machine is the latest example of its commitment to advancing the field. With its large diameter, hydraulic propulsion system, and constant pressure cutterhead, this TBM is well-equipped to tackle the challenges of tunnel construction in China's complex urban and geological landscape.