Tunnel Boring Machines
This page requires Flash Player version 10.
TUNNEL BORING MACHINES
Tunnel Boring Machines
HARD ROCK MACHINES
Single Shield TBM
A single shield machine uses pre-fitted segments to exert the blast force on the working face. Digging time represents approx 80% of operating time, the remaining 20% corresponding to segment fitting.
Click here for the 'Technical Data Sheet'.
Double Shield TBM
Double shield machines allow for raster tunnel excavation as the segments are fitted in concurrent operation time during blasting (digging). In this case, digging time approaches 100% of operating time. The rear shield is fitted with grippers.
Machine progress is a 3-step process:
1. Gripping of the rear shield onto the excavated surfaces,
2. Digging by the cutter head (front shield advance), and laying of the lining,
3. Rear shield advance (hence gripper advance) to the next digging position and back-up traction.
Click here for the 'Technical Data Sheet'.
Gripper TBM
Grippers are shoes that press radially against the walls of the excavated tunnel.
Contrary to shelded hard rock TBM, this tunnel-boring machine therefore does not rest against the lining. The force exerted by the grippers must be very high to prevent the thrust applied to the head from causing shield recoil.
SOFT GROUND MACHINES
Slurry TBM (Benton' Air®)
Developed and patented by NFM Technologies, the Benton' Air® tunnel-boring machine (Slurry TBM) is used for tunnel-boring in highly permeable unstable terrain, or under civilian structures sensitive to ground disturbances.
When digging in highly unstable or liquid terrain, the pressure exerted by the terrain is directly governed by the depth at which digging is performed. It is therefore necessary to balance the pressure exerted by the terrain: the front shield of the Slurry TBM is filled with excavated material, with the exception of one air-filled part. The pressure within this air bubble is subject to fine control. Bentonite injection waterproofs the working face and improves its resistance.
Earth Pressure TBM (EPB TBM)
NFM Technologies initiated the earth pressure with additive process in Europe. The EPB technology is suited for digging tunnels in unstable ground such as clay, silt, sand or gravel.
The front shield of the EPB TBM is filled with debris extracted by means of a screw conveyor. This screw compensates the pressure difference between the working face and atmospheric pressure. Foam injection renders the material more homogeneous, thus facilitating its excavation.
Click here for the 'Technical Data Sheet'.
DUAL MODE MACHINES
Dual Mode TBM
A dual-mode tunnel-boring machine can dig through very different geologies, earth and rock for example. In this case, the tunnel-boring machine is developed to receive two types of removal equipment, each one corresponding to a given type of ground.
Click here for the 'Technical Data Sheet'.
NFM TECHNOLOGIES 
VIEW TBM MOVIE VIEW RECENT PROJECTS
- Single Shield TBM
- Double Shield TBM
- Gripper TBM
Single Shield TBM
A single shield machine uses pre-fitted segments to exert the blast force on the working face. Digging time represents approx 80% of operating time, the remaining 20% corresponding to segment fitting.
Click here for the 'Technical Data Sheet'.Double Shield TBM
Double shield machines allow for raster tunnel excavation as the segments are fitted in concurrent operation time during blasting (digging). In this case, digging time approaches 100% of operating time. The rear shield is fitted with grippers.
Machine progress is a 3-step process:
1. Gripping of the rear shield onto the excavated surfaces,
2. Digging by the cutter head (front shield advance), and laying of the lining,
3. Rear shield advance (hence gripper advance) to the next digging position and back-up traction.
Click here for the 'Technical Data Sheet'.Gripper TBM
Grippers are shoes that press radially against the walls of the excavated tunnel.
Contrary to shelded hard rock TBM, this tunnel-boring machine therefore does not rest against the lining. The force exerted by the grippers must be very high to prevent the thrust applied to the head from causing shield recoil.
SOFT GROUND MACHINES
- Slurry TBM (Benton' Air®)
- Earth Pressure TBM (EPB TBM)
Slurry TBM (Benton' Air®)
Developed and patented by NFM Technologies, the Benton' Air® tunnel-boring machine (Slurry TBM) is used for tunnel-boring in highly permeable unstable terrain, or under civilian structures sensitive to ground disturbances.
When digging in highly unstable or liquid terrain, the pressure exerted by the terrain is directly governed by the depth at which digging is performed. It is therefore necessary to balance the pressure exerted by the terrain: the front shield of the Slurry TBM is filled with excavated material, with the exception of one air-filled part. The pressure within this air bubble is subject to fine control. Bentonite injection waterproofs the working face and improves its resistance.
Earth Pressure TBM (EPB TBM)
NFM Technologies initiated the earth pressure with additive process in Europe. The EPB technology is suited for digging tunnels in unstable ground such as clay, silt, sand or gravel.
The front shield of the EPB TBM is filled with debris extracted by means of a screw conveyor. This screw compensates the pressure difference between the working face and atmospheric pressure. Foam injection renders the material more homogeneous, thus facilitating its excavation.
Click here for the 'Technical Data Sheet'.DUAL MODE MACHINES
Dual Mode TBM
A dual-mode tunnel-boring machine can dig through very different geologies, earth and rock for example. In this case, the tunnel-boring machine is developed to receive two types of removal equipment, each one corresponding to a given type of ground.
Click here for the 'Technical Data Sheet'. NFM TECHNOLOGIES VIEW TBM MOVIE VIEW RECENT PROJECTS
