Explosion-Induced Vibrations During the Excavation of an Underground Space Under Preservable Masonry Buildings: Fid-Bau Portal

Explosion-Induced Vibrations During the Excavation of an Underground Space Under Preservable Masonry Buildings

Psarropoulos, Prodromos

Abstract The current study describes a “real-scale experiment” that was carried out few years ago at the Lavrio Technological and Cultural Park (LTCP) of National Technical University of Athens (NTUA), in Greece. It concerns the monitoring of explosion-induced vibrations during the construction of an underground environmental project, consisting of an underground space and two supplementary projects (i.e. an access tunnel and an access shaft). The aim was to monitor instrumentally the structural health of adjacent old masonry buildings which had been characterized as “preservable monuments” in the past. Note that the whole monitoring procedure was enforced by the Greek Ministry of Culture in order to minimize the possibility of damages to the sensitive buildings. The concept of the “experiment” has been the gradual increase in the magnitude of blasting during the excavation of the access tunnel, and the instrumental monitoring of (a) the oscillations at characteristic points on the ground and on the buildings, and (b) the development of pre-existing cracks on buildings to assess and minimize the potential impact of blasting during the construction phase of the underground space and the access shaft. After a brief description of the project and the prevailing geological – geotechnical conditions, a brief description of the pre-existing buildings is made, and the results of the measurements are given. Finally, the current norms of risk assessment due to explosion-induced vibrations are described, comparisons between recordings and norms are made, and useful conclusions are drawn for the distress of the buildings.