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(11) | EP 0 979 926 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Tunnel excavating process and tunnel excavator |
| (57) Provided are a tunnel excavating process which can reduce pressure required in excavation
and excavate under lower pressure than the prior art even if compressive strength
of base rocks is high, and a tunnel excavator capable of suitably executing the process.
A plurality of roller cutter groups are arranged at given intervals in an excavating
direction and in a direction vertical thereto, and points of roller cutters belonging
to each roller cutter group in contact with base rocks are located in the vicinity
of a difference in level portion formed in the base rocks to excavate the base rocks.
There is constituted a tunnel excavator 1 in which a plurality of roller cutter groups
3x are arranged at given intervals in an excavating direction and in a direction vertical
thereto on a cutter head 2 having a substantially conical shape. A boring head 4 can
be disposed coaxial with the cutter head 2 to bore a pilot tunnel 7. |