| 摘要 |
PROBLEM TO BE SOLVED: To provide a shield machine improved in the degree of freedom for setting the shape of an elliptical shield shaft, simplified in the constitution, reduced in the manufacturing cost, preventing generation of un-excavated area to be projected inward of a tunnel. SOLUTION: This shield machine 1 for excavating an elliptical shield shaft of approximately elliptical section comprises a cutter disk 3, a pair of planetary cutters 4 provided on its front part, a rotation mechanism for integratedly rotating these components and rotating a pair of planetary cutters 4, a pair of oscillation cutters 6 arranged on the right and left sides of the cutter disk 3, and a pair of oscillation mechanisms for oscillating the oscillation cutters 6. A center part of the elliptical shield shaft is excavated in an approximately square shape by the cutter disk 3 and a pair of planetary cutters 4, and the right and left parts of the center part are excavated by a pair of oscillation cutters. |
