The tunnel drilling rig null which is used for the enlargement construction method and its construction method of the existing sewage pipe

摘要

PURPOSE:To make effective removal of a segment pipeline, which has undergone secondary covering work, by cutting and removing the secondary covering simultaneously with or around the excavation of the natural ground. disassembling and removing the primary covering, and then constructing a new pipe duct. CONSTITUTION:Natural ground at the perimeter of an existing pipe duct 40 is excavated ring-shapedly by an outside cutter 20. An inside cutter 30 is rotated by a motor 33. With this, an inside propelling jack 50 is contracted and the inside cutter 30 is advanced, and only the secondary covering 42 of the existing pipe duct 40 is cut and removed. Then the jack 50 is elongated, and the inside cutter 30 is retreated, and a space for disassembly work for segment 41b is obtained. A joint bolt is cut by using this space for works, and the primary covering of the tail is disassembled. An outside propelling jack 29 is contracted, and a new pipe duct is constructed in the space generated. After construction of the new pipe duct, the outside propelling jack 29 is again elongated, and the peripheral part of the existing pipe duct 40 is excavated ring-shapedly while reaction force is given to the foremost of the new pipe duct. Thereafter the procedures are repeated, and pipe ducts are constructed one by one.