ABSTRACT
An insertion system, cylindrically enlarged slurry shield machine (capable of underground mechanical docking of tunnels with different diameters) was developed in order to meet the requirements of the surrounding environmental restrictions, cost reduction, and shorter construction period. The system is designed to carry out works for a series of subsections by one shield machine, which performs works ranging from excavating two tunnels of different diameters to docking with another shield machine under the ground without using a shaft. This paper summarizes the problems on the mechanical connection of the parent and child shield cutter-heads by extension spokes used on the machine and how to solve the problems.
