Effect of wall stiffness on ground deformations around deep excavations in stiff clay

摘要

The construction of underground infrastructure in urban environments requires careful assessment of ground movements and how these affect existing structures and services. The tendency in current industry practice is to perform, due to the complexity of soil-structure interaction, advanced numerical analysis for such an assessment. Increasingly three-dimensional finite element or finite difference analyses are applied in preference to two-dimensional analyses. This paper considers some of the issues related to the modelling of a retaining structure, used to support an excavation, in 3D finite element analysis. In particular, it is recognised that any form of a retaining structure (e.g. diaphragm wall) is not structurally continuous in its horizontal direction, as it is in its vertical direction. Using the example of a deep excavation in London this paper investigates how such a structural detail can be accounted for in a numerical analysis and the effects on the predictions of ground movements if such a detail is ignored.