A Tunnel Boring Machine (TBM) is an advanced tunnel construction equipment that excavates tunnels quickly and safely by rotating a cutting head to crush rocks or soil. Compared to traditional methods like blasting or manual digging, TBMs can excavate tunnels more efficiently and safely. TBMs are increasingly used in tunnel engineering, especially in the construction of long-distance and large-section tunnels.

　　I. Basic Components of TBM

　　1. Cutting Head:

　　The cutting head is the core component of a TBM, equipped with multiple cutting tools such as disc cutters, scrapers, and breakers. The design and configuration of the cutting head depend on geological conditions, with hard rock geologies typically using hard alloy or diamond tools, while soft rock or soil may require rotating blades or scrapers.

　　2. Main Drive System:

　　The main drive system provides power for the rotation of the cutting head, usually achieved through electric motors with power reaching several kilowatts.

　　3. Propulsion System:

　　The propulsion system pushes the TBM forward using hydraulic cylinders or mechanical devices, ensuring close contact between the cutting head and the tunnel walls.

　　4. Support System:

　　While advancing, the support system automatically installs prefabricated tunnel lining segments or sprays concrete to ensure tunnel stability.

　　5. Measurement and Guidance System:

　　Utilizing technologies such as lasers, GPS, or inertial navigation systems, the measurement and guidance system monitors the position and direction of the TBM in real-time to ensure accurate excavation according to the design alignment.

　　6. Muck Handling System:

　　Collects and transports the debris (muck) generated by cutting, typically including crushers, screw conveyors, and slurry treatment equipment.

　　7. Auxiliary Systems:

　　Including ventilation, lighting, power supply, lubrication, and cooling systems to ensure the TBM's normal operation.

　　II. Working Principle of TBM

　　TBMs excavate tunnels by placing a large rotating cutterhead or cutting blades at the tunnel face, gradually advancing and excavating the tunnel. Simultaneously, the TBM continuously pushes forward, transporting excavated soil or rock from inside the tunnel to the surface.

　　Cutting Operation: After starting, the main drive system rotates the cutting head, crushing the rocks or soil ahead.

　　Propulsion: Pressure from the crushed rock propels the TBM forward, with the propulsion system automatically adjusting thrust to maintain a stable advance speed.

　　Support: As the TBM progresses, the support system immediately installs prefabricated tunnel lining segments or sprays concrete to stabilize the newly excavated tunnel section.

　　Measurement and Guidance: The measurement and guidance system monitors the TBM's position and direction in real-time, ensuring accurate excavation along the design route, with necessary adjustments as needed.

　　Muck Handling: Debris generated during excavation is collected and transported by the muck handling system to designated locations, sometimes requiring crushing and slurry treatment.

　　III. Applications of TBM

　　TBMs are widely used in railway tunnels, road tunnels, water conservancy and hydropower tunnels, urban rail transit, mining tunnels, and other projects.