Three-dimensional modelling of the interaction between buildings and tunnelling operations

An extensive programme of research has been carried out at Oxford University on finite elementanalysis of the interaction between masonry buildings and ground movements induced by tunnelling. The focushas been on the development of a predictive tool for assessing the probable damage to buildings. This paperpresents a brief summary of the work, with reference to other more detailed papers. The method is illustratedwith reference to the case of the Ramsgate harbour approach tunnel, in which a large diameter tunnel in chalkwas excavated at very low cover directly beneath a row of cottages. Both field measurements and analyses revealthat in this case the building responds flexibly, following rather closely the greenfield settlements, which weresmall. The slight damage to the buildings was also correctly modelled

Three dimensional analysis of building settlement caused by shaft construction

ABSTRACT: An analysis of a case history of settlement damage to a masonry building, due to the construction of a nearby shaft, is presented. Three-dimensional finite element analysis is used, in which the non-linear behaviour of both the soil (a heavily overconsolidated clay) and the building is taken into account. Procedures are used to capture the construction process as realistically as possible. Comparisons are made between a variety of analyses (including separate analyses of the building and the soil, and a fully coupled analysis of the whole system), as well as with observations at the site. The principal comparisons are in terms of observed surface settlements and of the categories of cracking damage suffered by the masonry building. It is concluded that the analysis technique can model adequately the interaction between the building and the ground, but that details of settlement and damage patterns depend critically on assumptions about the structure and stiffness of the building and its foundation.

A tying scheme for imposing displacement constraints in finite element analysis

This paper describes the formulation of elements to connect finite element meshes of differing dimensionality. The formulation employs minimization using Lagrange multipliers. While this technique is already described in many texts, this paper demonstrates how particular types of connection may be implemented as independent tie elements. Ties for connecting 2D and 3D nodes and for 2D to 2D nodes are formulated in this paper and examples are given showing their application

Plastic response of circular footings on sand under general planar loading

Data from a set of tests of model circular footings on dense sand are presented. The footings were subjected to a variety of combinations of vertical, horizontal and moment loading. The tests were designed to provide the information necessary to construct a complete model of the footing behaviour, based on the concepts of plasticity theory. In particular, the tests provide detailed information about the shape of the yield surface, and so allow generalization of bearing capacity calculations to cases other than purely vertical loading. Information is also obtained about the hardening law and flow rule appropriate for a plasticity model, and the elastic response within the yield surface.<br/

Transferring a non-linear finite element code to the Oxford Supercomputer, Oscar

A complex three-dimensional finite element model has been developed to study the effects of tunnel construction on adjacent structures. The model uses an in-house finite element code in which complex simulations and non-linear material models have been developed. This paper describes the transfer of this code to a large parallel computer, and the improvements in performance that resulted from the move. The examination of the code, which was necessary for the transfer, also led to improvements in the serial version