Tunnelikoneet

Tunnelikoneet, also known as Tunnel Boring Machines (TBMs), are complex electromechanical devices used to excavate tunnels through the ground. These machines are typically used when the ground is stable enough to remain in place after the TBM has passed, and they are capable of excavating in a variety of geological conditions. The primary function of a TBM is to bore a full-face circular tunnel.

A typical TBM consists of a large rotating cutting wheel at the front, equipped with cutting tools. As the machine advances, the cutting wheel grinds away at the rock or soil, breaking it into smaller pieces. These excavated materials, known as muck, are then transported to the rear of the machine via a conveyor system. Behind the cutting head, a shield supports the newly excavated tunnel walls, preventing collapse. As the TBM advances, it can also install tunnel lining segments, often made of precast concrete, to provide permanent support.

TBMs come in various types, designed for specific ground conditions. Soft ground TBMs, for example, are equipped with a different type of cutting head and slurry or screw conveyors to handle unconsolidated materials. Hard rock TBMs, on the other hand, feature robust cutters designed to break through solid rock. The selection of a TBM depends on factors such as the geological makeup of the ground, the diameter and length of the tunnel, and the project's specific requirements. The use of TBMs allows for faster, more controlled, and often safer tunnel construction compared to traditional drill and blast methods, especially in urban environments or areas with sensitive ground conditions.