| 摘要 |
PROBLEM TO BE SOLVED: To provide a tunnel construction method, by favorably excavating a natural ground which does not allow blasting excavation and is difficult to excavate by a free-section excavator. SOLUTION: In the natural ground G where a tunnel regular pit 1 is constructed, a pilot drift 2 extending in the direction of an axis O1 of the tunnel regular pit 1 is lead-excavated to locate in a section of the tunnel regular pit 1, a plurality of radial holes 4 extending from the pilot drift 2 toward the outer periphery 1a of the tunnel regular pit 1 (the peripheral surface S of the tunnel regular pit drilling) are bored radially at predetermined spaces in the circumferential direction of the pilot drift 2 and also at predetermined spaces T2 in the direction of the axis O1 of the tunnel regular pit 1, a plurality of rock breaking holes 5 extending from a working face 6 to which the pilot drift 2 is opened to the direction of the axis O1 of the tunnel regular hole 1 are also bored, and the natural ground G where the radial holes 4 and the rock breaking holes 5 are bored is excavated from the working face 6 by a rock crushing machine 7. COPYRIGHT: (C)2009,JPO&INPIT
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