Abstract

Urban populations are likely to continue to grow which places additional pressure on existing transport networks. A potential solution to meet the increased demand is to go underground. Such subsurface infrastructure solutions have the potential to reduce congestion, pollution and noise and thus make our cities more liveable. However, new underground construction involves ground movements, which pose a significant risk to the built environment. Present risk management is primarily based on costly monitoring and damage prevention measures. Understanding and accurately predicting the interaction between excavation induced ground movements and existing buildings is crucial to reduce these cost.

The primary motivation of this work is to deepen the fundamental understanding of ground and building response to tunnel excavation in soft ground. This presentation begins by introducing geotechnical centrifuge testing to study tunnelling effects on surface structures. It will then move on to describe the performed experimental program including the techniques applied to conceptually model tunnelling-induced volume loss and to replicate realistic surface structures using 3D printed small-scale models. More precisely, the novel application of 3D printing to replicate detailed surface structures of brittle material properties, similar to masonry, and related experimental challenges are addressed. Subsequently, results that highlight the ground and building response to tunnelling subsidence will be presented. Specifically, the presentation will address: 1) the effect of the building-to-tunnel position on the shape and magnitude of vertical surface ground displacements, 2) the impact of surface structures on the tunnelling-induced volume loss, 3) the transfer of vertical and horizontal ground movements to the buildings and 4) the effect of building characteristics such as the façade opening area, the building length and the building layout on the soil-structure interaction. Finally, the experimental results are used to evaluate available methods for predicting the effects of tunnelling-induced ground movements on structures, after which recommendations for refinement of these methods are proposed.