ABSTRACT
There is often advantage in being able to obtain rapid theoretical solutions to analyses of the behaviour of geotechnical systems without having to resort to the full complexity of numerical modelling. It has been emphasised several times, in the context both of numerical modelling and of physical modelling, that it should always be possible to obtain supporting 'back-of-the-envelope' estimates of response to give reassurance that the results of the numerical or physical modelling are secure and that the governing phenomena are understood. These estimates may not be particularly precise but should be of the correct order of magnitude. Simple calculations can also be used to perform rapid parametric studies in order to reveal the most influential parameters and hence make more efficient the subsequent detailed numerical or physical modelling.
