The invention relates to a protective element (20) for connecting to a concrete element (10) of a tunnel lining, to the concrete element (10) and to the method for producing the concrete element (10). It is an object of the invention to provide a protective element (20) for a tunnel lining, or the associated concrete element, which ensures that the protective casing of the tunnel lining is better safeguarded against corrosive gases or liquids. The solution of the invention provides that the protective element (20) is produced from an injection-moldable plastics material, that a protective portion (21, 22, 23) is connected in a single piece to a seal (30), wherein the connection is gas-tight and liquid-tight, that the protective portion (21, 22, 23) is connected in a single piece to a connecting element (24, 25, 26, 27, 28), and that the single-piece connection is produced by injection molding of the plastics material.

The liner includes a rib formation with a transverse section configured to mechanically lock the liner to a concrete shell and a joint to allow the rib formation to flex. The joint for the rib formation can comprise a first side spaced apart from a second side with each joined to the transverse section to allow each side to flex with respect to each other. The space between the first side and the second side can be filled with a weld material to add rigidity to the rib formation while allowing it to flex. Each of the first side and the second side can be combined at the other end to a shell. The combined rib formation and shell are spirally wound to create the liner.

The liner includes a rib formation with a transverse section configured to mechanically lock the liner to a concrete shell and a joint to allow the rib formation to flex. The joint for the rib formation can comprise a first side spaced apart from a second side with each joined to the transverse section to allow each side to flex with respect to each other. The space between the first side and the second side can be filled with a weld material to add rigidity to the rib formation while allowing it to flex. Each of the first side and the second side can be combined at the other end to a shell. The combined rib formation and shell are spirally wound to create the liner.