A new methodology for carrying out triaxial laboratory tests, together with advanced numerical modelling, was developed by Prof. Marco Barla and subsequently adopted for tunnel-lining design in rock masses characterised by swelling behaviour.

The method makes it possible to determine the complete deformation state around the excavation. It is described in detail in the paper “Numerical simulation of the swelling behaviour around tunnels based on special triaxial tests”, published in Tunnelling and Underground Space Technology in 2008.

Research continues in this area through laboratory testing, numerical modelling and validation against available monitoring data from case studies.

The SHELVIP visco-elastic-plastic model was developed to assess the level of complexity required for a constitutive law to satisfactorily reproduce the time-dependent mechanical behaviour of complex geomaterials (Debernardi, 2008).

Current research applies and evaluates the model under different geological, geotechnical and construction conditions.

The main objective is to analyse the response of TBM-excavated tunnels in hard rocks under high in situ stresses, where the failure process is dominated by stress-induced fractures that may lead to spalling and/or strain bursts.

Continuum, equivalent-continuum and discontinuum models are considered, together with the combined Finite-Discrete Element Method (FDEM).

Building response to excavation, together with new and advanced monitoring tools, is investigated to improve the management of underground construction in congested urban environments.