STARTING AREA CONSTRUCTION METHOD OF SMALL-DIAMETER SHIELD

摘要

PROBLEM TO BE SOLVED: To provide a starting area construction method of a small-diameter shield which can equally arrange a small-diameter shielded tunnel, is sufficed with a small construction range, and excellent in economical efficiency.;SOLUTION: In order to construct an outer shell 1 by using this starting area construction method of a small-diameter shield, firstly, a pilot tunnel 43 is constructed in a form of communicating with an in-tunnel space of a main route tunnel 4 so as to be substantially parallel with a tunnel axial line of the main route tunnel 4, and located in a position apart from the main route tunnel (step 101), a cylinder body 61 is constructed by annularly extruding a box body 51 from the pilot tunnel by an expulsion method so that the main route tunnel 4 is surrounded with the pilot tunnel as a construction starting point (step 102), and a starting area 3 is constructed after forming an annular space 81 by excavating and removing a rock mass which is expanded toward the inside of the cylinder body 61 (steps 103 to 104), and integrating the annular space and the in-tunnel space 82 of the main route tunnel 4 to each other (step 105).;SELECTED DRAWING: Figure 1;COPYRIGHT: (C)2018,JPO&INPIT