EXCAVATION DIAMETER MULTISTAGE VARIABLE SHIELD EXCAVATOR AND SHIELD METHOD BY SHIELD EXCAVATOR CONCERTED

摘要

PURPOSE:To positively and efficiently excavate a tunnel having different excavation diameters by connecting a plurality of cutter heads to a plurality of shield cylinders so that the cutter heads can be separated from the shield cylinders by a coupling pin which can be operated by a hydraulic cylinder. CONSTITUTION:Shield cylinders 2, 3 and 4 are moved forward at a time while rotating cutter heads 5, 6 and 7 at once to excavate a tunnel and at the same time, the circumference of the tunnel is lined with a segment 16 in the tail section of a shield excavator 1. After that, when it reaches a point to change an excavation diameter of the tunnel, the cylinder 4 is separated from the cylinders 2 and 3. Then, a hydraulic cylinder 12 is operated to pull a coupling pin 11 out of a pin hole 14 of the cutter head 7, and the head 7 is separated from the heads 5 and 6. A tunnel having a diameter smaller than that of another tunnel is excavated by the excavator 1 consisting of the cylinders 2, 3 and heads 5, 6, and it is lined with the segment 16. In addition, when it reaches a point to change an excavation diameter, the cylinder 3 and head 6 are separated to excavate.