INVERT CONSTRUCTION METHOD IN ROAD TUNNEL, AND INVERT

摘要

PROBLEM TO BE SOLVED: To provide an invert construction method of a road tunnel which can be performed without interfering with high-speed traffic by widening a traffic lane, and an invert.SOLUTION: In an invert construction method of a road tunnel: a traffic lane 2 in a tunnel 1 is widened from a center line C1 of a tunnel cross section into an adjacent traffic lane to define a primary widened traffic lane 4 and a primary real work area 5 for excavation; a primary base course 6 is primarily excavated to expose a primary base end part 8 of a lining 7; straight steel pipes 11 are inserted from a primary recess into a secondary base course 10; primary concrete 13 is placed along a curve V and residual parts 14 of the straight steel pipes 11 are connected to the base end part of the primary concrete 13; and the primary base course is regenerated and temporary pavement 15 is constructed on the surface thereof. Subsequently, the adjacent traffic lane is widened to the traffic lane 2 side to define a secondary widened traffic lane and a secondary real work area; the secondary base course is regenerated in a manner similar to the case of the primary real work; and both the traffic lanes are restored to original width by constructing pavement over both the base courses.