| 摘要 |
PROBLEM TO BE SOLVED: To make crushing drilling possible in a large grain size gravel layer or a rock-bed section at single shielding of a slave shield machine by providing disc cutters for crushing a gravel layer on the face plate of a slave cutter head formed into a dome or a truncated cone. SOLUTION: A slave shield machine 2 concentrically received in a master shield machine 1 is provided with a cutter head 12. The slave cutter head 12 is provided with a dome-shaped face plate 12a and spokes similar to a master cutter head 7, and many disc cutters 8 are mounted on the front face and the outer circumferential part of the face plate 12a and the spokes, so that crushing drilling can be performed at a large grain size gravel layer or a rock-bed. The disc cutters 8 provided on the outer circumferential part of the slave cutter head 12 are arranged so as to direct obliquely outward against the shielding direction, the outer diameter of shielding is made outside of the inner diameter of the inner circumferential ring 7a of the master cutter head 7, and hence an impossible shielding territory is prevented from generating in the boundary part between the master shield machine 1 and the slave shield machine 2 at shielding in one body of master and slave. Hereby even at single shielding of the slave shield machine 2, crushing drilling in a large grain size gravel layer or a rock-bed section is made possible. |
