In 2016 I wrote a review paper to identify the state of existing knowledge and understanding of railway and highway embankment failures. The review considered field, laboratory and numerical approaches to understanding pore water induced slope failure, seasonal shrink-swell movement and progressive embankment failure.
The paper was co-authored by Prof. Glendinning and Dr Loveridge and supported by the EPSRC-funded iSmart project. The paper can be found here.
I have a Royal Academy of Engineering Industrial Fellowship (2017-18) which will enable me to support Network Rail in identifying improvements to earthworks’ management and maintenance. The collaboration will also lead to new teaching content and industrial links for students at the University of Bath.
Railway embankment failure (Photo courtesy of D. Hutchinson)
Highway slope failure (Photo courtesy of D. Patterson)
Earthworks in a changing climate
I am interested in the response of railway and highway earthworks to extreme rainfall events and in their potential behaviour in a changing climate. I have undertaken the following investigations:
An assessment of monitoring data collected during the extremely wet winter of 2000/2001, to better understand the types of embankment that are most at risk of failure during such extreme events.
Finite element modelling (Vadose/w) to explore the influence of foundation geology on pore water pressure increase within embankments during extremely wet winter weather.
An assessment of the British Geological Survey (BGS) landslide database to identify rainfall and soil moisture conditions associated with earthwork (embankment and cutting) failures between 2004 and 2014.
Finite element simulation of extreme summer pore water pressures (PWPs) at Charing embankment
Finite element simulation of extreme winter pore water pressures (PWPs) at Charing embankment
Slope failures between 2004 and 2014 compared with rainfall and soil moisture deficit (SMD)
Drystone retaining walls
I have undertaken investigations into drystone wall construction and wall integrity at road and railway sites in the Cotswolds (England), Snowdonia (Wales) and in the Cevennes (France). With my colleagues at the University of Bath, this has included fruitful interactions and collaborations with local (artisan) builders and with drystone retaining wall owners (e.g. local authorities).
Drystone retaining walls form an essential part of the infrastructure in hilly and mountainous regions, in both the developed and developing world. The construction of drystone retaining walls reflects the local building expertise and the types of locally available stone. The stones are assemble without mortar, to provide a low-energy, sustainable form of retaining wall construction to support roads, buildings, and agricultural terraces.
Publications describing this work can be found here
Thermal image of a drystone wall in France
Assessing the Ffestiniog Railway (Wales)
Old quay walls
I am interested in better understanding failure mechanisms in historic block masonry and brick retaining walls. My previous investigations have included an old quay wall (19th Century), constructed by John Rennie adjacent to the River Thames.
I have used laboratory-scale model testing and advanced limit equilibrium methods to better understand the deformation behaviour and the ultimate failure mechanisms of old quay walls. This will improve the stability assessment of walls supporting critical infrastructure or undergoing a change of use.
If you have a historic wall which may be of interest then please contact me.
CT imaging of fill soils
I have been exploring new ways to non-destructively visualise the structure of soils and measure their properties without disturbance.
I have used CT scanning to measure the size and distribution of pores, fissures and cracks in samples of embankment fill. This can be used to enhance our understanding of changes in soil structure within ageing earthworks in response to changing weather, a changing climate or change of use.
Publications relating to this work can be found here.