The TBM Tunneling Method: A Guide to Modern Excavation

The TBM Tunneling Method Explained

Mechanized tunneling using a TBM (Tunnel Boring Machine) has become the standard for major infrastructure projects. But how exactly does the TBM Tunneling Method work? Here is a breakdown of the process that allows us to build tunnels faster and safer than ever before.

The Cycle of Operation

Excavation: The rotating cutterhead is pushed against the tunnel face. Disc cutters fracture the rock or soil, which falls through the cutterhead openings. Muck Removal: The excavated material is transported from the face to the rear of the machine via screw conveyors or belts, and then out of the tunnel by train or truck. Advance: Hydraulic jacks push the machine forward. In shield machines, these jacks push against the previously installed concrete rings. Ring Building: Once the machine has advanced the length of a segment ring (usually 1.2 to 2 meters), the jacks are retracted. A robotic erector arm lifts precast concrete segments into place to form a complete ring. Grouting: The gap between the concrete ring and the ground is filled with grout to stabilize the tunnel and waterproof the lining.

Why It Beats Traditional Methods

Compared to "Drill and Blast," the TBM method is continuous, less labor-intensive, and causes significantly less vibration. This makes it the only viable option for urban tunnels under sensitive structures.

Ready to implement the TBM method on your project? Consult with the experts at Tunnel-Boring.com.