| 摘要 |
PURPOSE: To assemble a segment with high degree of accuracy to mechanize by carrying an invert segment having the central angle within a specific angle and first and second crown segments having the specific angle as the central angle in a shield machine to assemble. CONSTITUTION: An invert segment 10 having the central angleα>120 deg. and first and second crown segments 11 and 12 having the central angleβ(360 deg.-α)/2 are carried into a shield machine. Then, the inside and outside circumferences of the invert segment 10 are dressed with the inside and outside circumferences of the existing tunnel, the end 12b of the crown segment 12 is contacted to the end 10a of the invert segment 10, the end 12a is widened to the inside circumference of the machine to move with the end 12b as the center. Then, the other end 11b is widened to the inside circumference of the machine to move with the end 11a as the center. The ends 11b and 12a of the crown segments 11 and 12 are contacted to each other to complete a circular segment ring 13.
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