SHIELD FOR BORING TUNNELS WITH CAST IN-SITU PRESSED CONCRETE LNING

摘要

A sheathing unit has a surrounding sections press ring. It is mounted in a sheath-housing, and slides along the axis of the driving shield for construction of tunnels with monolithically pressed concrete cladding. Adjacent members (16) of the ring (6) are linked, but they are mutually displaceable lengthways. The second branching pieces (38) of each of the two-position hydraulic distributors are linked by an additional pipe (36) linked to a pressure pipe (35) via a pressure reducer (26) and non-return valve (25). These provide reduced pressure in the additional pipe and in the connected set of shield cylinders (2).