What is the difference between TBM and Roadheader? The differences between Tunnel Boring Machines (TBMs) and Roadheaders can be categorized as follows:

　　1. Design and Operation:

　　- TBM: Features a full-face rotating cutterhead that excavates the entire tunnel diameter simultaneously. It is typically shielded and includes integrated systems for lining installation (e.g., segment erectors) and continuous muck removal via conveyors.

　　- Roadheader: Equipped with a boom-mounted cutting head (often a drum with picks) that excavates incrementally. The boom allows for flexibility in cutting direction and shape.

　　2. Tunnel Shape and Size:

　　- TBM: Excavates circular tunnels of consistent diameter, ideal for large-scale projects (e.g., subways, hydroelectric tunnels).

　　- Roadheader: Capable of creating non-circular profiles (e.g., rectangular, arched) and is used for smaller, variable tunnels or mine galleries.

　　3. Applications:

　　- TBM: Suited for long, straight tunnels in urban infrastructure or large transportation projects.

　　- Roadheader: Used in shorter tunnels, mining, or projects requiring complex geometries (e.g., junctions, cross-passages).

　　4. Flexibility:

　　- TBM: Limited to linear paths; difficult to redirect once launched.

　　- Roadheader: Highly maneuverable, with the ability to adjust direction and handle irregular layouts.

　　5. Ground Conditions:

　　- TBM: Handles a wide range of conditions (soft soil to hard rock) using specialized variants (e.g., EPB, Slurry, Hard Rock TBMs).

　　- Roadheader: Best in soft to medium-hard rock or coal; less effective in highly abrasive or unstable ground without additional support.

　　6. Speed and Efficiency:

　　- TBM: Faster for long, uniform tunnels due to continuous excavation and simultaneous lining.

　　- Roadheader: Slower but adaptable, ideal for projects requiring frequent changes in cross-section or alignment.

　　7. Cost and Logistics:

　　- TBM: High initial investment and setup costs, economical only for large, straight projects.

　　- Roadheader: Lower upfront costs, modular design, and easier transportation, suitable for smaller or variable projects.

　　8. Safety and Support:

　　- TBM: Shielded design protects workers and allows immediate ground support via pre-cast segments.

　　- Roadheader: May require manual installation of supports (e.g., rock bolts, shotcrete), exposing workers to unsupported ground temporarily.

　　Summary: TBMs excel in large, linear tunnels with consistent geology, offering speed and safety. Roadheaders provide versatility in shape and direction, making them ideal for smaller, complex, or mining-related projects. The choice depends on project scale, geology, and required tunnel geometry.