A maintenance concept for concrete tunnel linings in soft soil conditions

In the European project TUNCONSTRUCT a life cycle cost method for management and maintenance of underground structures is developed. Within the project TNO is concerned with the durability of the concrete lining. In this paper the concept is explained by means of a case of a bored road tunnel (in soft soil) with exposure to de-icing salts (internal) and seawater (external). The example concerns a real structure, with input chosen such that at some point in time during the service life corrosion and spalling will occur and repairs will be needed. Moreover, for elucidating the optimization possibilities of the method two types of intervention are concerned: (1) conventional repair with a relatively short life of the repairs, such that new repairs will be needed during the remaining life of the tunnel and (2) cathodic protection with a relatively long life, so that only minor interventions are needed during the remaining life of the tunnel. © 2008 Taylor & Francis Group, London