Tunnel Boring Machine and applications in real world

Tunnel Boring Machine and applications in real world

1. TBM in tunnels

2. Tunnel Boring Machine works, we will divide its components into three parts: Cutting Head (front) Tunnel Field (middle) Trailing Gear (rear)   Tbm for Hard Rocks -shielded or open-type TBMs is used to excavate rocks with the help of disc cutters which are mounted on the cutter head. the excavated rocks are transferred to the belt conveyor through the cutter head openings. These rocks are then run through multiple conveyors to get them removed from the tunnel.

3. The Soft Ground TBMs have three main types of TBMs: Slurry Shield when the ground conditions are granular with very high water pressure. the cutter head with pressurized slurry, which is also used as a transporting medium when mixed with the excavated material before it is pumped to the cutter head back  spoil from the slurry are filtered using the Slurry separation plants to reuse it in the construction process. Earth Pressure Balance when the soft groundwater is less than 7 bars of pressure. the cutter head not only uses disc cutter but also a combination of tungsten carbide cutting bits, drag picks and carbide disc cutters. where the excavated material supports the tunnel face. It later gets plasticized with the help of slurry such that it is transportable. The spoil is then transferred into a TBM with the help of a screw conveyor that allows the pressure to remain balanced without any use of slurry. Open Face Type method of excavating with no frontal support, relying on the fact that the ground being excavated will stand up with no support for a brief period, making it suitable to be used with rock types having strength up to 10MPa.

4. Stages of TBM Construction   Excavate the launching and retrieve shaft Assemble the TBM at the launching shaft Cut and excavate the tunnel The TBM then arrives in the retrieval shaft and gets dismantled for transportation.