TUNNELLING MACHINE

摘要

The invention relates to a tunnelling machine of the type comprising a cylindrical shield (2), having an excavating element (8) at the front end, said shield (2) being composed of a number of blades (16, 18) which lie adjacent in the peripheral direction of the shield and which are displaceable in the longitudinal direction of the shield (the so-called "self-advancing blade system", known in the technical world, and developed by Westphalia Luenen) and which is characterized in that means are provided which cause a cylinder (12) of sheet material to emerge from the leading end of the shield, along its periphery, and during its movement in forward direction, said cylinder enclosing the blades.