Geotechnical Stability Analysis

51st Rankine Lecture 2011

Prof Scott Sloan

Historically, geotechnical stability analysis has been performed by a variety of approximate methods that are based on the notion of limit equilibrium. Although they appeal to engineering intuition, these techniques have a number of major disadvantages, not the least of which is the need to presuppose an appropriate failure mechanism in advance. This feature can lead to inaccurate predictions of the true failure load, especially for cases involving layered materials, complex loading, or three-dimensional deformation.

This lecture will describe recent advances in stability analysis which avoid these shortcomings. Attention will be focused on new methods which combine the limit theorems of classical plasticity with finite elements to give rigorous upper and lower bounds on the failure load. These methods, known as finite element limit analysis, do not require assumptions to be made about the mode of failure, and use only simple strength parameters that are familiar to geotechnical engineers. The bounding properties of the solutions are invaluable in practice, and enable accurate solutions to be obtained through the use of an exact error estimate and automatic adaptive meshing procedures.

The methods are extremely general and can deal with layered soil profiles, anisotropic strength characteristics, fissured soils, discontinuities, complicated boundary conditions, and complex loading in both two and three dimensions. Following a brief outline of the new techniques, stability solutions for a number of practical problems will be given including foundations, anchors, slopes, excavations, and tunnels.

About the speaker

Prof Scott Sloan Laureate Professor, University of Newcastle

Scott Sloan is Laureate Professor and Director of the 220-strong Australian Research Council (ARC) Centre of Excellence for Geotechnical Science and Engineering at the University of Newcastle, NSW, Australia. He is an elected Fellow of the Australian Academy of Science, the Australian Academy of Technological Sciences and Engineering, the Royal Academy of Engineering, and the Royal Society of London.

In the recent past, Prof Sloan has received the Monash University Alumnus of the Year Award in Civil Engineering, was named as NSW Scientist of the Year and was cited by Engineers Australia as one of Australia’s Top 100 Most Influential Engineers.

Scott is the recipient of various accolades including the 2000 Telford Medal and 2007 Telford Premium from the ICE. He has held visiting professorships universities internationally and is a board member for the (IACMAG).

Scott currently serves on the Council of the Australian Academy of Science and is one of the world’s most highly-cited geotechnical researchers with a Scopus H-index of 42 and 16 papers with >100 citations. His research interests include computational stability analysis, nonlinear finite element algorithms, geotechnical modelling, soft soils, modelling unsaturated soil behaviour, nonlinear optimization methods, and georemediation.

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