CONSTRUCTION METHOD FOR VARIABLE CROSS SECTION OF TUNNEL, AND TUNNEL BORING MACHINE FOR USE IN IT

摘要

PROBLEM TO BE SOLVED: To enable an easy change such as the width reduction of a part of a cross section of a tunnel.;SOLUTION: This construction method comprises: a step of assembling a D-type bulkhead segment S3 in such a manner that the bulkhead segment S3 continues into an existing circular segment S1; a step of installing an impervious bulkhead ring 2, the inner periphery of which is equipped with a tail sealing device 8, in such a manner that the bulkhead ring 2 continues into the bulkhead segment S3; a step of assembling a D-type segment S2 in the impervious ring in such a manner that the D-type segment S2 continues into the existing bulkhead segment S3; a step of connecting the impervious bulkhead ring to a boring machine body; a step of sequentially assembling the D-type segment S2; a step of disconnecting the impervious bulkhead ring from the boring machine body, while connecting the impervious bulkhead ring to the final D-type segment 2 when the boring machine body reaches a final position where the width of the cross section of the tunnel is reduced; a step of assembling the circular segment S1 in such a manner that the circular segment S1 continues into the impervious bulkhead unit and the final D-type segment S2; and a step of connecting the circular segment S1 to the impervious bulkhead ring and the final D-type segment S2.;COPYRIGHT: (C)2007,JPO&INPIT