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Heritage masonry structures require detailed monitoring during nearby underground construction, to address the concerns of building owners and mitigate uncertainties relating to the soil–structure system. This paper discusses innovative displacement and strain monitoring of a listed masonry church undergoing ground movements due to nearby tunnelling in London Clay. In addition to conventional surveying and tilt monitoring, laser scan displacement monitoring and fibre optic strain sensing was conducted. Prior to construction, point clouds of the structure were used to map pre-existing geometric distortions in the structure. During construction, detailed monitoring of displacements and strains was conducted across the building facades and the tower. The same techniques were also used to monitor the painted dome of the church where conventional displacement monitoring was not feasible. With a focus on the new engineering insight provided by the innovative monitoring techniques, the impact of the underground construction activities on the church is discussed in this paper. The proposed sensing techniques provide new data on the influence of pre-existing damage and tunnel advance on soil–structure interaction. [ABSTRACT FROM AUTHOR]

Computational modelling of the effect of underground excavations on adjacent structures has shown great potential to aid the assessment of tunnelling-induced damage to structures. However, the complexity of the mechanisms involved and the uncertainties connected to the use of sophisticated constitutive laws still limit the application of numerical modelling in civil engineering practice. This paper evaluates the effectiveness of soil models with different levels of complexity when predicting tunnelling-induced displacements of the soil surface, and consequently the assessment of building deformations. The performance of a non-linear elastic, a linear elastic–perfectly plastic and a critical-state-based kinematic hardening soil model were compared with the results of centrifuge testing of a tunnel excavation in sand. Results demonstrated that both the non-linear elastic and the kinematic hardening models are suitable to reproduce the effect of soil–structure interaction on the soil surface displacements and the building deformations, while also demonstrating the limitations of these methods in predicting local soil strains around the tunnel itself. [ABSTRACT FROM AUTHOR]

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 soil–structure 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. [ABSTRACT FROM AUTHOR]

Building monitoring and protection are important components of underground projects in urban areas. Typically the procedures applied for the assessment of settlement-induced damage to buildings are based on simplified assumptions that do not take into account soil–structure interaction. Assessment methods based on the relative stiffness between the structure and the soil exist, but they are rarely applied in practice due to concerns about the accuracy and reliability. The primary aim of this work is to use the large amount of monitoring data provided by the Crossrail project in London to improve understanding of building performance and existing damage assessment methods. The paper gives an initial overview of the available monitoring data by presenting four representative case studies for load-bearing masonry buildings on shallow foundations. Structural data are then used to evaluate the consistency of predictions produced by different relative stiffness formulations. The results show the effect of building stiffness on the soil surface settlements and clarify the effects of various assumptions made during prediction. The conclusions highlight opportunities to improve prediction procedures and the need for more detailed monitoring data for future tunnelling projects. [ABSTRACT FROM AUTHOR]