Athens metro extension project to piraeus ground borne noise and vibration assessment and control

ATTIKO METRO S.A., the state company ensuring the development of the Athens Metro network, has recently initiated a new extension of 7,6 Km, has planned for line 3 of Athens Metro from Haidari to Piraeus "Dimotikon Theatre" towards "University of Piraeus" (forestation), connecting the major Greek Port with "ELEFTHERIOS VENIZELOS" International Airport. Piraeus extension is consists of a TBM (Tunnel Boring Machine) 2 tracks & NATM, tunnel sections, as well as 6 stations and a forestation (in NATM tunnel) at the end of the alignment. In order to avoid the degradation of the urban acoustic environment from ground borne noise and vibration during metro operation, the assessment of the required track types & possible noise mitigation measures was executed, and for each section and each sensitive building, the ground borne noise and vibration levels will be numerically predicted. The calculated levels were then compared with ground borne noise and vibration levels criteria. The necessary mitigation measures were defined in order to guarantee, in each location along the extension, the allowable ground borne Noise and Vibration max. levels inside nearby sensitive buildings taking into account alternative Transfer Functions (TF) for ground borne noise diffusion inside the buildings. Ground borne noise levels were proven to be higher than the criterion where special track work is present and also in the case of the sensitive receptor: "Dimotikon Theatre". In order to reduce the ground borne noise levels to allowable values in these sections, the installation of tracks and special track work on a floating slab (FS) was assessed and recommended