The interaction mechanisms between surface structures and tunnelling-induced ground movements were investigated through centrifuge testing. Although numerous studies have considered this soil-structure interaction problem, previous experiments have neglected important building characteristics and field data inherently contain numerous uncertainties related to the soil, the structure and the tunnelling procedure. Consequently, the interpretation of results and validation of computational models can be problematic. In this study, tunnelling beneath three-dimensional printed structural models with varying building characteristics (i.e. position, length and facade openings) was simulated in a centrifuge. The experimental results demonstrate that tunnelling induces soil displacements at the surface and subsurface that are notably altered due to nearby structures. Specifically, different amounts of vertical and horizontal ground movements, soil dilation and widening of settlement troughs were observed. Building distortions and horizontal building strains were also affected by the relative position of the building to the tunnel, the building length and the area of facade openings. The experimental results provide important data for the evaluation of current design methods and verification of computational models.

Understanding the building response to tunnelling-induced settlements is an important aspect of urban tunnelling in soft ground. Previous centrifuge modelling research demonstrated significant potential to study this tunnel-soilstructure interaction problem. However, these recent studies were limited by simplified building models, which might result in uncertainties when interpreting the building performance to tunnelling subsidence. This paper presents an experimental modelling procedure and the results of a series of centrifuge tests, involving relatively complex surface structures subjected to tunnelling in sand. Powder-based three-dimensional (3D) printing was adopted to fabricate building models with realistic layouts, facade openings and foundations. The 3D printed material had a Young's modulus and a brittle response similar to historic masonry. Modelling effects and boundary conditions are quantified. The good agreement between the experimentally obtained results and previous research demonstrates that the soil-structure interaction during tunnel excavation is well replicated. The experimental procedure provides a framework to quantify how building features affect the response of buildings to tunnelling subsidence.

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In this paper, the response of buildings to tunnelling-induced ground movements is studied with elastic and elastoplastic continuum solutions that consider the structure as an equivalent simple beam. A comparison is made between these simple solutions and centrifuge test data to provide insights into flexural and axial building deformations of low-rise bearing wall structures on strip foundations; the influence of wall openings and the foundation scheme on the equivalent beam bending stiffness is also addressed. Subsequently, the effects of structural continuity across greenfield sagging and hogging regions on tunnel-structure interaction are investigated. Finally, the continuum solutions are used to propose a modification factor formulation that accounts for the change in settlement trough shape (compared to the greenfield) due to soil-structure interaction. This formulation, for example, accounts for the change in transverse length of the hogging and sagging regions of a building due to soilstructure interaction, eliminating the need to divide the building at the greenfield inflection points when calculating modification factors. The proposed formulation, which is compared with numerical, experimental and field data from previous research, is shown to better predict flexural building deformations.

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