Boring Company Launches Prufrock-MB1in Nashville. How a Tunnel Boring Machine (TBM) Works.

How a Tunnel Boring Machine (TBM) Works — Step by Step

STEP 1 — LAUNCH
The TBM is assembled in a launch pit dug at the start point. The machine is pushed forward into the ground using hydraulic jacks.

STEP 2 — CUTTERHEAD ROTATION
A giant circular disc (cutterhead) at the front spins continuously, fitted with hardened steel disc cutters and teeth that grind and scrape through rock or soil.

STEP 3 — GROUND PRESSURE MANAGEMENT
Pressurized slurry or earth paste is pumped to the face of the cutterhead to balance underground water and soil pressure — preventing collapse.

STEP 4 — MUCK REMOVAL
Broken rock and soil (called muck) is scooped into openings in the cutterhead, then carried backward through the machine via a conveyor belt or screw conveyor and loaded onto rail cars or trucks to be removed.

STEP 5 — SHIELD ADVANCE
Hydraulic thrust cylinders push the entire machine forward by bracing against the last installed concrete ring — moving the TBM inch by inch.

STEP 6 — SEGMENTAL LINING INSTALLATION
As the machine moves forward, a robotic arm called an erector picks up pre-cast concrete segments and assembles them into a ring behind the cutterhead — forming the tunnel wall instantly.

STEP 7 — GROUTING
Liquid grout is injected into the gap between the concrete rings and the surrounding ground to lock the tunnel lining in place and prevent ground settlement above.

STEP 8 — CONTINUOUS CYCLE
Steps 2–7 repeat continuously — cut, remove muck, advance, install ring, grout — 24 hours a day until the TBM reaches the exit point.

STEP 9 — BREAKTHROUGH
The TBM emerges at the destination pit — called a breakthrough. The machine is then dismantled or repositioned for the next drive.

STEP 10 — FIT-OUT
The raw tunnel is fitted with trackway, electrical systems, ventilation, lighting, and safety systems ready for vehicles or trains.

Видео Boring Company Launches Prufrock-MB1in Nashville. How a Tunnel Boring Machine (TBM) Works. канала Curious Club TV