| 摘要 |
PROBLEM TO BE SOLVED: To excavate a tunnel having a rectangular cross section by simple constitution. SOLUTION: The shield machine has a shell section 10 protecting the inside to load from the outside and having a rectangular cross section, a cutter head 20 conducting the excavation of a circular cross section in front of the shell section 10 and a corner-angle cutter 30 performing excavation in a region between the outer circumference of the cutter head 20 and the external shape of the shell section 10. The corner-angle cutter 30 contains arms 32 rocked within the corner-section range of the shell section 10 centering around the corner section of the shell section 10 and cutter bits 34 installed to the arms 32. |
