Pickhaver, J A (2006) Numerical modelling of building response to tunnelling. PhD thesis, University of Oxford, UK.
Abstract
The construction of underground tunnels in soft ground in urban areas involves the potential for ground movements caused by the tunnelling to affect existing surface structures. Masonry structures are at particular risk of crack damage. Conventional empirical building assessments do not fully capture all aspects of this soil-structure interaction situation. Numerical methods are increasingly used for such problems. It is common practice in empirical and numerical methods to model a building as an elastic beam in 2D. The objective of this thesis is the development of a new approach to the numerical modelling of masonry buildings using surface beams in 3D. In phase one of this project, finite element analyses of elastic and masonry facades are undertaken and the traditional beam method of modelling them is assessed. New equivalent elastic surface beams are developed, the properties of which account for the dimensions and openings in facades which were found to influence the response to settlements. Equivalent masonry beams are also developed which have a constitutive model that accounts for the different response of masonry buildings in hogging and sagging. Timoshenko beams are chosen to model the facades and these beams were implemented into the OXFEM finite element program with full 3D capability along with the new constitutive beam models. Example masonry structures were modelled in 3D using the new surface beams in phase two. Tunnel construction was simulated under the buildings and the response of the beams compared to a full masonry building model. Example analyses included buildings both symmetric and oblique to the tunnel. Results showed that the equivalent elastic beams accurately simulate full masonry building response in sagging regions. Parametric studies confirmed the choice of equivalent beam parameters and the impact of different relative stiffnesses. The equivalent masonry beams displayed the same good agreement in sagging but were less accurate in hogging. In phase three, finite element models are used to compare ground movements and structural response of buildings using the 3D equivalent masonry beam method and observed data from the construction of the London Underground Jubilee Line Extension. The surface beams showed good agreement with the observed building responses in both sagging, where the building response was essentially rigid and in hogging where a more flexible response was observed.
| Item Type: | Thesis (Doctoral) |
|---|---|
| Thesis advisor: | Burd, H J and Houlsby, G T |
| Uncontrolled Keywords: | beams; masonry; tunnel; tunnelling; mason; London |
| Index terms: | tunnel construction, dimension, urban area, modelling, beam, program, interaction, building assessment, tunnelling, masonry structure, London, tunnel, mason, movement, finite element analysis |
| Subjects: | software systems, infrastructure and transport systems, practitioner, engineering analysis, structural engineering, behavioral psychology, urban form and morphology, building construction, health monitoring assessment and metrics, Geography, civil engineering, health behaviours and lifestyles, asset management, analytical methods |
| Topics: | Geographical Context, Urban Studies, Digital Applications, Health and Safety, Research Practice, Business Strategy, Roles and Professions, Design Practice, Engineering Principles |
| Descriptive scope: | 3 PCA |
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