ABSTRACT
NTT’s existing telecommunication tunnel has been an obstacle in the construction of a seaside-line subway shield tunnel planned by the Kobe Municipal Transportation Bureau. To ensure that the subway is as convenient as possible and to reduce construction costs, the existing underground tunnel was altered. This paper presents new technologies for a highly reliable ground freezing method, which makes it possible to remove the obstructive part of the existing tunnel and construct a new structure under the existing tunnel without affecting surroundings and telecommunication services.
