Particle-scale insights into the compression and shearing of clay

Professor Glenn McDowell

Glenn McDowell graduated with a first-class degree in engineering at Cambridge in 1993 and stayed to study for a PhD with Malcolm Bolton. His work was on “clastic soil mechanics” – that is, the soil mechanics of crushable grains and this culminated in the widely cited 1998 Géotechnique paper “On the micro mechanics of crushable aggregates”.  

He was awarded a Goldsmiths Junior Research Fellowship at Cambridge in 1996 and moved to Nottingham as a newly appointed lecturer in 1998. He has pursued the micro mechanics of normal compression and critical state soil mechanics ever since. In 2005, he was awarded the Silver Medal by the Institute of Materials, Minerals and Mining and in the same year, published a theoretical explanation in Géotechnique for the normal compression line.

In 2013, he published, with tonight’s co-author John de Bono, the widely cited Géotechnique paper “On the micro mechanics of one-dimensional normal compression,” proving the theory he had proposed in 2005. In 2006, he was promoted to a chair and in 2013, he was awarded a Higher Doctorate DSc degree by the University of Nottingham- the university’s highest award for research.  

He continued to work on micro mechanics of critical state soil mechanics and in 2018, he and John de Bono were awarded the BGA Medal for the Géotechnique paper “Micro mechanics of drained and undrained shearing of compacted and overconsolidated crushable sand”.  After this the authors turned their attention to clay in an attempt to explain why the behaviour of clay is, in so many ways, like sand, when the behaviour at a particle level could not be more different.  

In 2023, they were awarded again the BGA Medal for the Géotechnique paper “Particle scale simulations of the compression and shearing of kaolin clay”, which is the subject of tonight’s talk. Glenn has authored or co-authored over 100 journal papers, including many on the mechanics of railway ballast. He was Head of the Department of Civil Engineering at Nottingham from 2014 to 2024 and is a Fellow of the ICE.

Dr John de Bono

John de Bono studied for his PhD at the University of Nottingham, under Professor Glenn McDowell. His thesis was entitled “Discrete element modelling of cemented sand and particle crushing at high pressures”.

After completing his PhD in 2013, he stayed at Nottingham as a Research Fellow, developing computational models to investigate and explain the behaviour of a variety of soils. He worked on several EPSRC projects, studying the discrete element modelling of sands, railways ballast and most recently clay.

In particular, the modelling of crushing has been of interest.  His work with his co-author, Glenn McDowell, won the BGA Medal for 2018 and again in 2023. John was promoted to Senior Research Fellow at Nottingham in 2023 before moving into finance.  Since 2023, he has worked in the energy industry as an analytical consultant.