Building response to line 9 EPB tunnelling in Barcelona: a case study

Abstract

The paper presents the field monitoring data and a three-dimensional finite-element analysis aiming at back-analysing the response of a multi-storey framed building affected by the EPB excavation of a 12 m diameter tunnel for the L9 Metro Line. Key aspects of this case study are the excavation section being characterised by mixed face conditions, a curved tunnel axis alignment, a cover-to-diameter ratio between 2.5 and 3, and the skewed building orientation with respect to the tunnel. In particular, the soil profile in the area consists of alluvial and detrital deposits of Quaternary age laying above Miocene siltstone and argillite. These demanding conditions led to poor performance of the large diameter EPB machine near the building, significant ground movements, and cracking of several non-structural elements of the building. Numerical results are discussed in the light of available monitoring measurements.