| 摘要 |
PROBLEM TO BE SOLVED: To provide a widened part construction method of a tunnel and a structure of a tunnel widened part in which a widened part between parallel tunnels is constructed safely and in a short time and segments of the parallel tunnels and a widened segment forming a widened arch are joined firmly and safely.SOLUTION: In accordance with a widened part construction method of a tunnel, a preceding construction section and a following construction section are alternately installed between parallel tunnels to be widened in an axial direction of the tunnels. First of all, a widened segment is installed while removing segments of the parallel tunnels in the preceding construction section. Continuously, the following construction section remaining between the preceding construction sections is constructed similarly to the preceding construction section. In a structure of a tunnel widened part, while removing segments of the parallel tunnels, a widened arch bridging parallel segments with a radius larger than a curvature radius of the parallel tunnels is joined to a widening segment having unequal thickness in which a widened segment tip portion to be the widened arch is made as thick as the segments of the parallel tunnels and the thickness is then increased gradually in a tapered shape. |
