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In this paper, the influence of the foundation configuration (raft or separate footings) on tunnel–soil–framed building interaction is investigated using geotechnical centrifuge testing. Tunnelling-induced soil movements and deformation fields, framed building displacements and structure shear distortions (with associated modification factors) are illustrated. Framed building stiffness and footing bearing capacity are also evaluated experimentally. Results show that the foundation configuration plays an important role in determining the ground response to tunnelling, affecting soil displacement fields, as well as the distribution of soil shear and volumetric strains. In particular, foundation settlements and differential horizontal displacements are larger for separate footings compared to raft foundations. The effects of building width, weight and eccentricity (with respect to the tunnel) on foundation settlements and structural distortions are quantified for separate footings and contrasted against results for raft foundations. The modification factor of the maximum building shear distortion is linked to the relative soil–building shear stiffness; interestingly, for buildings with similar values of relative stiffness, the level of shear distortion within framed buildings is lower for separate footings than rafts. [ABSTRACT FROM AUTHOR]

The construction of tunnels in urban areas inevitably entails the interaction with existing structures. While the effect of tunnel excavation on masonry structures has been thoroughly studied, the response of framed buildings has not been widely investigated in the past. In this paper, a parametric study of the response to tunnelling of reinforced concrete framed structures founded on strip footings is carried out using the Finite Element method. The foundations and the structural members of the building are modelled with a sufficient detail and a realistic contact law is employed to simulate the interaction between the foundation and the adjacent soil. Results are summarised in terms of deflection ratios and modification factors for horizontal strains. It is shown that the structural stiffness, mainly provided by the foundation, on average reduces the differential settlements and the horizontal displacements of the frame as compared to greenfield conditions. However, in contrast with what discussed in previously published papers, while the deflection ratio in sagging reduces as the number of floors becomes larger, it increases in hogging, which always occurs at the ends of the foundation. This evidence appears to be related to the non-uniform contact pressure at the soil-foundation interface and to the peculiar load distribution associated to the frame geometry. [ABSTRACT FROM AUTHOR]