ABSTRACT
Construction of a local train access to El Prat Airport in Barcelona was completed in 2019. The project included passing under Terminal T2, airport apron and one runway by means of EPB (earth-pressure-balance) tunnelling in soft quaternary deltaic deposits. The prediction of displacements and the study of potential damage to the terminal structure and to the runway was carried out simulating the tunnel-soil-structure interaction by means of a 3D model, which was also used to design a specific monitoring plan for the terminal building. The model adopted an appropriate constitutive model for the deltaic soft ground and was calibrated by means of monitored greenfield sections. In addition, specific analyses addressing the potential blowout risk under the runway as well as the influence of face and tail grouting pressures on tunnelling performance were carried out. The paper also includes the study of a number of factors underlying a problem of large ground loss around a secant pile access shaft and the remedial actions undertaken to complete the works under safe conditions.
