Lezkairu Utilities Tunnel

Underground utility tunnels present some unique constructional and operational considerations that require specific approaches to achieve optimal system performance and maintenance. From the construction point of view, perhaps the main issue is the avoidance of the accumulation of water in the surroundings of the structure. The design and construction of an adequate drainage system is important in avoiding added pressure on side walls and subslab pressure on the bottom concrete slab, as well as avoiding contact of water with the structure that could result in infiltrations that could impair the functionality of the construction and lead to ensuing and major repair costs. From the point of view of management and operation, some aspects of the overall design, such as coordinating different economic agents and ensuring the safety and integrity of the facility (from accidents as well as sabotage), require considerations that are not present in other typical civil engineering projects. This article relates these considerations to a specific case of an underground utility tunnel, or gallery, of approximately 7,885 m that was recently built for a new urban expansion area in the city of Pamplona, Spain. (C) 2011 American Society of Civil Engineers.