Professor Poulos is distinguished for his work in geomechanics, notably in developing a unified theory for the behaviour of structural foundations. His major contribution relates to the analysis and design of pile foundations. He has replaced empirical methods by scientific assessment involving both the elastic and elastic-plastic regions of soil behaviour. The results have been presented in a form readily usable by practising engineers. His work has attracted favourable international attention and the solutions he has derived have been widely applied. He has served as a consultant on many significant civil engineering projects in Australia and overseas.