Derivation of model parameters for numerical analysis of the Ivens shaft excavation

The prediction of induced ground movements and the potential damage to existing structures and services is paramount when building deep excavations in an urban environment. In order to obtain a reasonable prediction advanced constitutive models need to be employed, so that the behaviour of the soil can be adequately reproduced under different stress conditions. The calibration of such models is complex and often requires optimisation, as a large number of parameters need to be determined from the available ground investigation data, while also ensuring their consistency with the initial ground conditions. This paper presents the calibration process of advanced constitutive models employed to simulate the excavation of the Ivens shaft in Lisbon, Portugal. The data from both historic and new laboratory and field testing is employed in the calibration procedure. In order to assess and validate the suitability of the derived model parameters, a back-analysis of the nearby Baixa-Chiado metro station excavation is carried out and its results are presented and discussed.