| 摘要 |
PROBLEM TO BE SOLVED: To excavate a rectangular section by providing expansible cutters on excavation cutters circularly excavating, and controlling the expansible quantities, in a shield machine of rectangular external formed section in the machine shell. SOLUTION: A shell 1 of a shield machine is projectingly formed with semicircular parts 11 on the respective angle parts of the lengthwise rectangular section as a whole, and circular arc parts 12 on the side faces. Three sets of main cutters 2 are arranged in the lengthwise direction on the front of the partition wall 13 of the shell 1, angle part cutters 4 are arranged on the respective semicircular parts 11, and expansible cutters 3, 31 are arranged on the respective cutters 2, 4 capably of being projected and housed. The main cutters 2 are controlled by inverter so as not to interfere with each other, and the projecting quantities and the projecting ranges of the expansible cutters 3, 31 are controlled by computer, so as not to interfere with each other, and so as to be able to excavate the excavation ranges usefully. Consequently, by controlling to expand/ contract the expansible cutters 3, 31 of comparatively simple construction, the rectangular section can be excavated so as not to leave any non-digged part. |
