Mike Jefferies, PEng
Any soil can exist over a range of void ratio (or its alternate identity, density). Critical state soil mechanics (CSSM) developed from practical concerns of avoiding liquefaction failures into a theory linking a soil’s void ratio to all aspects of its mechanical behaviour. However, there is a widely held perception that CSSM is an ‘over idealized’ construct put forward by Cambridge University which has no relevance to real engineering (see Wikapedia...) – and which some advocate should not even be taught. This Lecture considers the development of CSSM from a historical perspective, illustrating the simplicity of the underlying ideas, and the wide range of contributors, and which leads to a proper representation of soil behaviour in a formally generalized framework using the state parameter. This generalization works, with considerable detail, for real soils ranging from clays to sands. There is particular application to liquefaction, the cause of many dam failures (from Calaveros a century ago through to the recent failures of Fundao and Cadia).
A Senior Consultant of Golder Associates, Mike is a registered Canadian professional engineer with some 40 years experience in offshore platforms, dams, and ground improvement. Strongly influenced in his early years by Professors Bob Gibson, Alan Bishop, and Peter Wroth, Mike has pursued an interest in theoretical soil mechanics despite working as a consulting engineer. A keynote speaker/author at international conferences on liquefaction, hydraulic fill construction, engineering mechanics, and offshore construction, Mike has published some eighty papers (approaching 5000 citations) and is co- author of the influential book Soil Liquefaction: A Critical State Approach. Mike is the originator of NorSand, an invited contributor to Geotechnique, the Canadian Geotechnical Society’s Fall/2012 Cross- Canada Lecturer, presented the 2014 Šuklje Lecture, and was the 2018 Jenning’s Lecturer; he was awarded a Telford Premium for geotechnical research in 2017.