TUNNEL CONSTRUCTING METHOD

PURPOSE:To establish a pre-lining construction method, by which tunnel excavation is made upon preliminarily covering the periphery of the tunnel in excavation and which allows easy and uniform provision of the pre-lining. CONSTITUTION:At a cut face 2a in the foremost part of a tunnel being excavated, a reinforcement groove (a) is provided along the outside surface of the tunnel. In the reinforcement groove (a) a number of reinforcing members 10 are inserted in such a way as joining one another. Each reinforcing member 10 is previously equipped with a joining part for mutual joining. Also the reinforcing member 10 is provided with a cavity 13 to generate communication between adjoining reinforcing members 10 in the reinforcement groove (a) previously, so that a space for placing mortar is secured in the reinforcement groove (a) in which the reinforcing members 10 are inserted. Then mortar is injected into the cavities in the reinforcing members 10, and thereby the members 10 in the groove (a) are joined together in a single piece. The inside of the groove (a) is excavated. and tunnel is constructed.