| 摘要 |
PURPOSE:To achieve the safety by carrying out the outbreak of the natural ground around the predetermined enlargement region by means of an overcutter for forming an enlarged part, and by excavating forward making the rear shield of enlargement constituent members, and making the forward shield of a rotary cutter shield machine. CONSTITUTION:The outbreak of the natural ground around the predetermined enlargement region is carried out by means of an overcutter 4 so as to conform to the enlargement shape, and at the same time mud is pressurized and injected. Every time the excavation proceeds, enlargement seal constituent members 13, 13' are assembled, and enlargement side surface forming members 21 are pushed out by a pressing device 25 for forming the enlargement part, and a front reaction receiver 30 and a rear reaction receiver 31 arc constructed. And in the inside of the members 21, a tail seal 36 and a rear shield jack 35 are equipped, and then by making the rear shield 34 of the members 21 themselves, and making the front shield of a shield machine 1, an enlargement segment 37 is constructed in the inside of the rear shield 34, and also the jack 35 is extended to drive the shield machine 1 forward. Thus, the excavation can be safely carried out. |
