METHOD OF ENLARGING TUNNEL FOR ROAD, HIGHWAY OR EXPRESSWAY WITHOUT BLOCKING TRAFFIC

摘要

PROBLEM TO BE SOLVED: To provide a construction method of enlarging a tunnel for a road, an expressway or a railway without blocking a traffic. SOLUTION: A tunnel enlarging method comprises a first step of boring a tunnel by sampling soil between an ideal profile of a tunnel to be enlarged, and an existing tunnel 2 (the size of the ideal profile differs in dependence upon a characteristic of the soil to be sampled), a second step of laying a single or a plurality of final coatings composed of corner stones 3, which has been previously manufactured, in the vicinity of a front end part of a bore (with intervals of 2 to 3 m) through the intermediary of the sample (having a size corresponding to the boring or drilling carried out at the first step) with in an active vault process, and a footing structure (inverted arch) is built as an option in a third step.