Arcuate precast tunnel lining segments

An arcuate tunnel-lining segment having two angularly spaced, longitudinally and radially extending opposite first ends, two axially spaced, angularly and radially extending opposite second ends, and radially spaced inner and outer surfaces bounded by said ends, said segment comprising:

• a body of precast concrete bounded by said ends and said surfaces;
• an axially extending packing strip of laterally compressible material, said strip being embedded in said body of precast concrete so as to extend axially of said body from one of said second ends to the other of said second ends at a location which is intermediate said first ends;
• said strip also extending radially from said outer surface to said inner surface, thereby dividing said body into two angularly adjoining segment parts separated from one another by said strip and having corresponding faces engaging said strip;
• a plurality of connecting means each having a central portion penetrating laterally through said strip, and two opposite end portions embedded in said body;
• said connecting means thereby holding said segment parts together with said faces thereof in confronting alignment with one another against laterally opposite faces of said strip while permitting movement of said faces of said segment parts towards one another by permanent deformation of said strip in compression when said tunnel lining segment is subjected in use to excessive external compressive loading.