Combined Loading of Shallow Foundations on Clay

Prof. Guy Houlsby, Harvey Burd, A.M. Puzrin (Technion, Israel) and S. Frydman (Technion, Israel)

This work was sponsored by the University of Oxford, ICI, Foreign and Commonwealth Office

Many foundations, particularly those offshore, are subjected to combined vertical, horizontal and moment loading. Whilst vertical loading is well understood, further work is needed to understand the behaviour of foundations under combined loadings. Three-dimensional finite element methods are being used to study the stability of shallow foundations on clay under a variety of loading conditions. The studies have involved a simplified two-dimensional analysis, and the development of new interface elements for two and three dimensional analysis. The main research programme has involved use of three-dimensional stability analysis to establish `benchmark' solutions for the response of circular footings under combined vertical, horizontal and moment loading. Comparisons are being made with both closed-form solutions for simplified forms of the problem, and with numerical solutions using the FLAC program. The numerical models developed during this research have also been compared with the results of laboratory scale model tests that have recently been completed at Oxford.