Abstract: A device for joining two members together such as concrete segments for a tunnel lining ring includes a first sleeve for fitting in one of the members to open at a surface thereof and a second sleeve for fitting in the other member. A connecting pin with external ribbing fits in both sleeves, which have internal ribbing, the ribbing of the connecting pin and/or the ribbing of at least one of said sleeves being of resilient material and extending in a substantially parallel direction at an inclined angle to a longitudinal axis of the connecting pin when it is, in use, inserted in the sleeves. The bore of one sleeve is of greater cross-sectional area in one dimension than the bore in the other sleeve, in which other bore the connecting pin can engage as a tight fit, while being able to engage in the firstmentioned bore and traverse it in said one dimension.

Abstract: Arcuate concrete segments of a tunnel lining are joined together by means of a recess in a segment edge having a pair of abutment members projecting into the recess to define a constriction therein, the abutment members forming a pair of abutment surfaces facing inwardly of the constriction, and a screw-threaded headed bolt in an adjacent segment, the segments being positioned edge to edge with the bolt inserted in the recess and moved relatively to each other so that the bolt head engages the abutment surfaces. The recess is accessible from inside the lining to allow the bolt head to be tightened.

Abstract: A tunnel lining comprises a plurality of arcuate segments connected to one another by connecting elements. Each connecting element protrudes from one segment and engages in a recess defined by an adjacent segment. Each recess is considerably larger than the connecting element and contains means for clamping the connecting element to one wall of the recess.

Abstract: A concrete segment for a tunnel lining, having an end connectable to an end of another identical segment abutting thereagainst by means of connecting dowels insertable from an end of the segment remote from the abutting end thereof or from one side of the segment into two channels within the segments, each channel extending through an end of the segment and into the end of said abutting segment, the channels being disposed at an angle to one another whereby the segments are held together when the dowels are in position.