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Author(s): Jorge Machado de Carvalho
Abílio Cavalheiro
Pedro Teixeira
Title: Tunneling in an urban critical area - a case study
Issue Date: 2007
Abstract: A 700m road tunnel crossing very heterogeneous granite formations within a critical area of thecity of Porto, Portugal, in which around 400m were excavated below groundwater according to NATM principles,has been open to public use in 2005. The average excavated section area is 100m2 with a cover varyingbetween 2,7m and 21m. The concerned area is quite challenging from a geological/geotechnical point of view very heterogeneous Porto granite rock mass overlaid by residual soil as well as from a technical/environmentaland social point of view intense traffic, densely constructed and under construction areahaving some problematic old nearby buildings with delicate foundations. The question of whether or not explosivesshould be used in such an environment has been a very controversial issue. Following various geotechnical,geophysical, vibration surveys, reports and feasibility studies, the tunnel has been successfully excavatedusing mainly blasting techniques and, whenever necessary, mechanized means. During the tunnelexcavation a comprehensive seismic vibration monitoring survey took place aiming at preventing damagerisks as well as optimizing subsequent blasting diagrams. The present report, following a brief summary ofsome project key issues regarding namely the final feasibility study, adjusted in-situ strategies during the excavationworks, monitoring procedures and safety measures, presents seismic vibration monitoring datatreatment procedures and an example of the promising preliminary results aiming at improving the geological/geotechnicalmodel inference along the tunnel alignment.
Subject: Ciências geofísicas
Geophysical sciences
Source: Underground space the 4th Dimension of Metropolises (Vol. 2)
Document Type: Artigo em Livro de Atas de Conferência Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Livro de Atas de Conferência Internacional

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