Development of a Soil-Specific CPT Interpretation Method for Partially Drained Penetration
This PhD project will be based at the University of Toronto with a 16 month stay at the University of Melbourne.
University of Toronto and University of Melbourne will be co-admitting an outstanding PhD student to conduct leading-edge research on an important geotechnical problem regarding interpretation of in-situ state of silty materials such as mine tailings. The successful applicant will be admitted into a program that includes stays at both institutions, with funds available to cover the cost of travel in addition to the normal research funding. The applicant will be awarded degrees from both institutions upon successfully completing their program requirements. The four-year PhD program includes taking courses at University of Toronto and conducting mostly analytical research at both universities. The ideal start time is September 2021.
Tailings storage facilities (TSF) are man-made earth structures used for storing mining waste, comprised of fine minerals and water left behind during the extraction process. They exist at the intersection of economics, safety, and sustainability. The mining industry needs better engineering practices for assessing and improving existing TSFs, designing new TSFs, and disposal processes motivated by: recent liquefaction-induced catastrophic failures of TSFs, economic challenges demanding reductions in tailings disposal costs, and evolving regulatory and social pressures to improve the safety and sustainability of tailings storage. Non-plastic granular soils, such as tailings, can lose all or part of their strength in a process called liquefaction. Soils’ resistance to liquefaction mainly depends on how densely-packed their particles are. Liquefaction potential is assessed by estimating soil density from its resistance to a penetrating probe. The Cone Penetration Test (CPT) is the predominant site characterisation tool since it provides a wealth of information with fast and inexpensive application. The cone penetration process has a complicated interaction with the pore water in often silt-rich tailings, because the rate of generation of excess pore water pressures due to the penetration and the rate of dissipation of the pressure away from the cone tend to be comparable in tailings. This makes interpretation of CPT results particularly challenging. University Melbourne and University of Toronto have joined forces to produce tailings-specific CPT interpretation methods by accounting for the complicated nature of soil, and interaction of soil, water and the advancing cone.
The jointly supervised PhD student will accomplish the following objectives through their work at both universities:
- Months 0-8, Toronto
- Course work and comprehensive exam
- Months 9-24, Melbourne
- Developing a coupled CPT model in ABAQUS
- Months 25 to 48, at Toronto
- Validating the results of the model against available experimental data
- Performing parametric studies to understand various influences on CPT response
- Developing interpretation method
A/Prof Mason Ghafghazi (University of Toronto)
Applications close February 22, 2021