TUNNEL EXCAVATING PROCESS AND TUNNEL EXCAVATOR

摘要

Provided are a tunnel excavating process which can reduce pressure required inexcavation and excavate under lower pressure than the prior art even ifcompressivestrength of base rocks is high, and a tunnel excavator capable of suitablyexecuting theprocess. A plurality of roller cutter groups are arranged at given intervalsin anexcavating direction and in a direction vertical thereto, and points of rollercuttersbelonging to each roller cutter group in contact with base rocks are locatedin thevicinity of a difference in level portion formed in the base rocks to excavatethe baserocks. There is constituted a tunnel excavator 1 in which a plurality ofroller cuttergroups 3x are arranged at given intervals in an excavating direction and in adirectionvertical thereto on a cutter head 2 having a substantially conical shape. Aboring head4 can be disposed coaxial with the cutter head 2 to bore a pilot tunnel 7.