This Website is not fully compatible with Internet Explorer.
For a more complete and secure browsing experience please consider using Microsoft Edge, Firefox, or Chrome

Computing for Geotechnical Design: Equilibrium, Strength, Strain, Dilation and Superposition

Computing for Geotechnical Design:Equilibrium, Strength, Strain, Dilation and Superposition 

View Webinar Recording


Some basic principles of mechanics were reviewed, using examples to show how they are important to practical design. Equilibrium is the fundamental requirement of many engineering calculations, and it is important to ensure that all forces can be transmitted into the ground that is able to resist them; computer programs that consider only part of the equilibrium may be insufficient. Modern finite element programs are easy to use, but it is essential that users cling to a sound grasp of soil mechanics and behaviour, and constantly ask themselves if the model in use is suitable for the current task; in particular dilation is important in controlling the strength of undrained or confined soils. Engineering courses tend to concentrate on stress states and stress analysis, but strain is much easier to observe and sometimes gives important warnings of impending problems. Finally, the principle of superposition was carefully taught, with emphasis that it only applies in linear situations; but in practice, this limitation is often forgotten.


​​​​COGAN Project



David Quinn, NAFEMS

An Introduction to COGAN
Dr Andrew Lees, Geofem

Computing for Geotechnical Design: Equilibrium, Strength, Strain, Dilation and Superposition
Dr Brian Simpson, OBE FREng MA PhD FICE Eur Ing
Arup Fellow, Honorary Professor at the University of Nottingham

Q & A Session



This webinar was the first of two sponsored by the COGAN project, which was funded by the EU under the Leonardo initiative. For some years there has been a need in the geotechnical industry to address the inconsistent implementation of increasingly powerful numerical analysis software (e.g. finite element analysis).


Previous benchmark studies have suggested that the inconsistency is primarily a result of users of analysis software lacking the necessary competency.

Therefore, the primary goal of COGAN is to improve competency in geotechnical numerical analysis.

Further information is available on the project website COGAN Project ( more information )


Webinar Presenters

Dr Brian Simpson OBE  FREng MA PhD FICE  Eur Ing

Arup Fellow,  Honorary Professor at the University of Nottingham


Dr Brian Simpson OBE  FREng   MA PhD  FICE  Eur IngDr Brian Simpson is an Arup Fellow, a principal of Arup Geotechnics and an Honorary Professor at the University of Nottingham, UK.  He has worked on a wide range of geotechnical and ground-structure interaction problems, maintaining particular interests in numerical modelling, retaining structures and tunnels.  He presented the BGA Rankine Lecture in 1992and a State-of-the-Art report on Geotechnical Analysis and Design at the 2009international conference of ISSMGE. Since the early 1980’s, he has been involved in the development of Eurocode 7 (Geotechnical Design), having been a member of its drafting panels and vice-chairman of the CEN (Comité Européen de Normalisation) committee on Eurocode 7 (SC7).  He has authored two commentaries on Eurocode 7 and several papers on various related issues.  He is the current chair of ISSMGE Technical Committee TC205 on Safety and serviceability in geotechnical engineering and of the BSI committee on geotechnical codes, B/526. He is often the UK delegate to SC7 and is a member of several of the “Evolution Groups” set up to propose further developments of Eurocode 7.


Dr Andrew LeesDr Andrew Lees

Andrew Lees is Director of the geotechnical analysis consultancy Geofem and coordinator of the COGAN project.