Ground borne noise and vibration transfer function inside sensitive neo-classic buildings from Piraeus metro tunnel during TBM's operation

Abstract

Attiko Metro S.A., in view of the additional development of Athens Metro network, has fully initiated the new extension of 7.6 km, for line 3 extension from Aghia Marina to Piraeus Dimotiko Theatre, towards “University of Piraeus” (forestation), connecting the significant Piraeus Port with “Eleftherios Venizelos” International Airport. During the operation of this major urban subway rail transit system, vibrations are expected to be generated. These vibrations are transmitted through the soil and cause vibrations in neighbouring structures. Especially in urban areas, these vibrations are a consequence of the vehicle forces acting from the wheels onto the track in local imperfections. The propagation of ground vibrations from a subway urban rail transit system inside adjacent buildings is mainly governed by the transfer function (TF) of vibration diffusion from the tunnel wall or tunnel invert towards the soil surface at the façade and the interior of two sensitive neoclassical and heritage buildings of great aesthetic and historical value e.g. the Municipal theatre of Piraeus and the Elementary school at Deligianni Street. During the construction of the extension of Athens Metro to Piraeus in both areas a methodology is proposed using as source of vibration: (a) the TBM operation (considered as a linear source), and (b) a point source based on an impact force at the tunnel invert. Both set ups were tested in the above sites in order to determine the necessary TF of the rail vibration diffusion inside the given geological media demonstrating the vibration attenuation values in 1/3 octave band analysis. The proposed metrological approach aims to ensure a high accurate estimation of the expected vibration and ground borne noise levels in each receptor, during operation, and assess possible negative effects on local communities from the metropolitan railway-induced ground vibrations © Proceedings of the 26th International Congress on Sound and Vibration, ICSV 2019. All rights reserved.