Enhanced mechanical strength of vegetated soil through transpiration

Climate change threatens the stability of infrastructure slopes, which form a large proportion of the European transport network. Slope failures due to increasing intense rainfall have already resulted in significant socio-economic loss across the Europe. Slope revegetation is identified as a more environmentally friendly and aesthetically pleasing stabilisation technique, when compared to other high-embodied-CO2 methods such as sprayed concrete cover. However, there are series of research questions at the interface of unsaturated soil mechanics and plant biophysics relating to this application that, if answered, will allow better engineered and widespread deployment of this ‘green’ solution. Many of these questions relate to the effects of plant transpiration on slope stability.

The aim of this PhD project is to develop and apply new testing methods to quantify the effects of plant transpiration on the hydro-mechanical behaviour of vegetated soil. The research will be predominantly based on laboratory testing to identify the effects of transpiration-induced suction on mechanical shearing and its induced volumetric behaviour of unsaturated vegetated soil. Detailed soil-root interaction including interface sliding and root straining will be investigated. Key soil properties (such as water retention curve) that govern the root-water uptake capability of vegetated soil will also be identified. Output from this research will provide a comprehensive high-quality dataset that could help improving the understanding of soil-water-root interaction.

The successful candidate will predominantly implement the experimental work at the University of Dundee (UoD) and the James Hutton Institute (JHI; the largest agricultural/environmental research institute in the UK). The candidate will be directed by two supervisors with a background in Geotechnical Engineering (at UoD) and Plant and Soil Science (at JHI).

Application must attach the following supplementary Information:
 CV
 Personal statements detailing
- Why you are interested in pursuing a PhD degree;
- Why you are interested in working on this project;
- What you would bring to the project; and
- What you would hope to gain from the project
 Two academic references
 Degree certification and transcripts

Applicants will be shortlisted and an interview will be arranged in early August 2014. Expected start date October/November 2014.

The evaluators in assessing the applications will be looking for evidence closely matching the majority of the following attributes:
• Clarity and focus of applicant's statement of purpose and potential for higher degree studies;
• Research experience, resulting in a paper presentation, publication in a scholarly journal or equivalent output to date;
• Degree of interest expressed by faculty / potential supervisors in working with the applicant as graduate student;
• Writing / communication skills as revealed through the statement documents attached in the application; and
• Status and quality of the applicant's references