Improvements in or relating to methods of erecting tunnel linings.

摘要

The disclosure relates to a method of erecting a tunnel lining using a tunnelling shield (40) comprising the steps of erecting a ring of segments (10) within the shield, each segment having a recess (20) around an outer peripheral edge thereof to provide, in the erected ring, a recess around the outer periphery of the ring of segments at the leading end of the ring in the direction of advance along the tunnel. The shield is then advanced with respect to the erected ring until the trailing end (41) of the shield locates in said recess in the leading end of the ring. The ring of segments is expanded against the tunnel wall by separating adjacent segments (10a) at at least one location around the ring whilst supporting the tunnel wall at that location against collapse by a cover sheet (29) and a supplemental segment (25) is then inserted between said adjacent segments to complete the ring.