Abstract: Joints are provided between the members of a pair of elements, such as a pair of concrete tunnel lining segments which are secured together in compression by a fastening arrangement with a gasket between the end faces of the segments. The gasket has a multiplicity of spaced recesses or apertures to prevent the gasket from creating a surface tension in the end faces when the joint is subjected to compression.

Abstract: The disclosure relates to a tunnel lining ring made up of a plurality of pre-cast arcuate concrete tunnel lining segments (10,11). The segments providing the lower part of the ring are formed with a recess (17) around the inner surface thereof to receive a secondary lining (18) in the completed tunnel to enable the inner surface of the invert of the tunnel to be graded as required and hence eliminate irregularities caused during the construction of the tunnel.

Abstract: A tunnel lining comprises a plurality of arcuate concrete tunnel lining segments. Each segment has at each circumferential end thereof two semi-cylindrical grooves spaced apart along the end and extending partway across the end. One of the grooves has two semi-circular hoops projecting from the end of the segment across the groove at spaced postions along the groove and the other groove has a single semi-circular hoop projecting from the end of the segment across the groove. Two segment ends are located together with respective hoops in alignment and tapered pins or other fastening devices are driven into the aligned hoops to draw and hold the segment ends together in compression.

Abstract: A tunnelling shield has a rearward rotatable part having a spiral rearward end to engage a forward end of a spiral tunnel lining. A drive mechanism rotates the rearward shield part as further tunnel segments are laid one by one in the shield end against the previous segment to be erected. Rams advance the shield as the rearward end rotates to allow a newly erected segment to engage the tunnel wall.