Previsional Acoustic Impact of the site work of the new metro line in Copenhagen

The City Circle Line (in Danish Cityringen) is a future expansion of the metro of Copenhagen that consists of two tunnels and 17 stations, all at 30 meters below ground level. The line, that should be operative in 2018, allows to connect some important areas of the cities of Copenhagen and Frederiksberg, replacing a part of the current bus services. The works needed for the construction of the Cityringen are quite noisy and the corresponding impact on the population is expected to be relevant. In order to evaluate the acoustic impact of the site work, simulations have been carried out taking into account noise regulations and site specific conditions of the municipalities of Copenhagen and Frederiksberg. Particular attention was paid in the characterization of the noise power emission of the various machineries used in the different phases of the construction, as well as in the analysis of vibrations. The goals of the paper are to describe the methodology used for the acoustical simulations and for the proposal of mitigation measures technically feasible.