| 摘要 |
PURPOSE:To enhance the hardening on standing of a cover cylinder and a ground gate by providing a copy cutter for excavation larger than a shield diameter on the rotating radial side end part of a cutter, and stirring a liquid soil improving agent hardening on standing with injection. CONSTITUTION:A mud adding material injection nozzle to a cutter head 10 is opened, whereby a mud adding agent is injected simultaneously with excavation to regularly add a fixed mud pressure onto a facing surface 12, and a fluid cement soil improving material hardening on standing is injected into the ground from the injection nozzle 15 of a copy cutter 14 at each spoke top end of the head. The excavated sediment and the mud adding material are kneaded and discharged, and a reaction is given to a cover cylinder 6 by a hydraulic jack 4 to assemble and extend segments 7. The ground on the outside of the outer circumferential surface of a shield cylinder 2 is stirred and kneaded to form an improved layer 17, and the outer circumference of the cylinder 6 is closely buried therein. Hence, the ground and the cylinder are integrated by hardening on standing, and subsidence of ground can be prevented. |
