ABSTRACT
The paper makes a survey on the general criteria for tunnel design with regard to vibration attenuation, with contributions from various experiences. The criteria used in this paper are a collection of knowledge arriving from the Technical University Munich TUM– since decades a strong point of reference for track design and validation – and MM SpA – the leading Italian company for metro design and construction. The most effective method to reduce the mitigation of noise and vibration at the source is the installation of mass-spring-systems. A resilient supported mass is decoupling the track from the tunnel construction. The perfect operation of a mass-spring system essentially depends on the correct design with regard to the natural frequencies due to bending of the track slab. However, the trends in design are opposed regarding divided planning procedures of tunnel structures with minimized cross sections for standard track. Constricted cross sections are limiting the installable mass, connected with increased bending of the track slabs and increased strain of the resilient bearings. Bigger tunnels bring about another advantage, which is the higher mass of the tunnel itself that acts as a dynamic decoupler of vibrations from tunnel to ground. Vibration mitigation has to be involved during the first planning phases of a tunnel, to optimize technical and economical features of tunnel and track.
