The invert operation method in the road tunnel which features

摘要

PPROBLEM TO BE SOLVED: To solve the following problems: a joint has to be provided on the center line of a tunnel cross section because the invert is a member for converting a force from the batholith to an axial force by a curved line and transferring it; connection in a misaligned position is not preferable; and a method for providing a pit in ground below a traffic lane makes costs high in the case of a long tunnel. PSOLUTION: The width of a traffic lane 2 is temporarily expanded to the inside of an adjacent traffic lane 3 from the center line C of the tunnel cross section; a primary base course Ga is excavated on the side of a primary narrow traffic lane 3a; a steel pipe is arranged across the center line in a second base course from an emerging primary recess; its remaining portion is connected to a primary base end 1b; the primary base course is regenerated by filling the primary recess; the primary narrow traffic lane 3a is expanded to the inside of a primary widened traffic lane 2a; a secondary base course is excavated on the side of a secondary narrow traffic lane 3b; an end of the steel pipe in an emerging secondary recess is connected to a secondary base end; and the width of the secondary narrow traffic lane and that of the secondary widened traffic lane 2b are restored to original conditions of them by filling the secondary recess. PCOPYRIGHT: (C)2010,JPO&INPIT