SHIELD MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a shield machine capable of smoothly advancing a front shield cylinder toward a distal part for excavation even when an unexcavated part is left in an inner surface part of a tunnel shaft in finishing the tunnel shaft to the planned shape by the excavation using a cutter part having a large number of cutter bits arranged in the radial direction around a rotary shaft in a forward part of the advancing direction of the front shield cylinder. SOLUTION: In this shield machine in which a cutter part 10 having a large number of cutter bits 11 arranged in the radial direction around a rotary shaft is provided in a forward part in the advancing direction of a front shield cylinder to excavate a tunnel, an auxiliary cutter bit 20 to cut an inner surface part of a tunnel shaft by the thrust is provided on a tip surface 3A of the front shield cylinder in order to finish the sectional shape of the tunnel which is previously excavated by the cutter part 10 to the shape along the outer surface of the front shield cylinder 10.