Shield tunneling method null for existing tube withdrawal and new establishment tube construction

摘要

PURPOSE: To excavate the ground around an existing pipe in an arbitrary cross section and remove the existing pipe and execute the construction of a tunnel in arbitrary cross section. ;CONSTITUTION: A shield machine 1 having a cutter 4 capable of rotating eccentrically in non contact with an area around the existing pipe 25 is installed outside the existing pipe 25 where the cutter 4 is used to excavate a spot around the existing pipe 25 in arbitrary cross section. After the excavation, the shield machine 1 is driven forward. When a tunnel has been excavated, the existing pipe 25 is cut inside the shield machine 1 and removed.;COPYRIGHT: (C)1995,JPO