CONSTRUCTION METHOD FOR SIDEWALL PILOT TUNNEL TYPE TUNNEL AND ITS STRUCTURE

摘要

PROBLEM TO BE SOLVED: To provide a construction method for a sidewall pilot tunnel type tunnel and its structure for shortening a construction term and reducing cost of construction as much as possible.;SOLUTION: This construction method comprises a sidewall pilot tunnel forming process for excavating and forming a pair of sidewall pilot tunnels 6, 6 at both of right and left side part positions in a main pit 4 by preceding the excavation of the tunnel main pit 4, a concrete sidewall forming process for forming concrete sidewalls 12 supporting a timbering 10 in the main pit 4 in the pair of pilot tunnels 6, 6 over the predetermined length by placing concrete successively, and a tunnel main pit forming process for forming the main pit 4 by installing the timbering 10 by stretching over upper faces of a pair of sidewalls 12, 12 while excavating between the pilot tunnels 6 and 6 after the sidewalls 12 are hardened. Ruler members 30 for prescribing top face part lines and inner face part lines of the sidewalls 12, 12 are arranged on wall surfaces of the pilot tunnels 6, 6 and concrete 40 is sprayed into a space prescribed by the ruler members 30 by a plurality of times in many layers to fill the space with the concrete and form the sidewalls 12 having the desired shape in the concrete sidewall forming process.;COPYRIGHT: (C)2009,JPO&INPIT