R.M. Hardy Keynote Address – Dr. Ryan Phillips
Centrifuge Modelling – 'A Mari usque ad Mare'
The 2019 R.M. Hardy lecture reviews the application of geotechnical centrifuge modelling across Canada over the past three decades. This advanced physical modelling technique for simulating and studying geotechnical problems was first used in Canada in 1984 at Queens University, and has since been practised at five different institutes nation wide. After introducing its fundamental principles, its application to the most famous foundation case study will be discussed. Canadian examples from a diverse range of modelling programs from some of these institutes will then be presented, with a focus on the 25 years of experience at C-CORE. These programs will include two major infrastructure projects, static and dynamic liquefaction studies, and pipeline designs in two different cold regions.
Ryan Phillips, PhD, PEng, is Principal Consultant for geotechnical engineering at C-CORE and Director of their Dr. Jack Clark Geotechnical Centrifuge Facility in St. John's, Newfoundland. After graduating as a civil engineer in 1978, he worked in industry for Soil Mechanics Limited in UK and abroad. Ryan then obtained his doctorate in 1986 from Cambridge University, where he managed their centrifuge centre until joining C-CORE in 1993. He has over 30 years of geotechnical engineering experience in applied research and consulting. Ryan has managed numerous industry and jointly funded programs, mostly related to pipelines and offshore foundation systems. Ryan is cross-appointed as an Associate Professor in Memorial University, is the author or co-author of over 200 publications, and has received the CGS Meyerhof, Quigley and Stermac Awards. He represents the Canadian Geotechnical Society as a Member on both ISSMGE Technical Committees TC104 on Physical Modelling in Geotechnics and TC209 on Offshore Geotechnics. Ryan is a board member of the Canadian Foundation for Geotechnique, and an Associate Editor of the Canadian Geotechnical Journal. He is a Fellow of the Engineering Institute of Canada and a recipient of their CPR Engineering Medal for his service to CGS.
CGS Colloquium 2019 – Dr. Kathy Kalenchuk
Mitigating a fatal flaw in modern geomechanics: understanding uncertainty, applying model calibration, and defying the hubris in numerical modelling
Numerical modelling has become one of the most widely used design tools in geomechanics. It has undergone substantial, rapid change in recent decades, with comparatively small advances in the methodologies for data collection and parameterization of rockmasses required for model input. We are now, and have been for some time, in a situation where modelling capabilities vastly exceed our ability to characterize fractured rockmasses and parameterize design models. The data limited nature of geomechanical engineering often results in high degrees of uncertainty in design input. Unfortunately, this uncertainty is too commonly lost (or forgotten) somewhere between numerical data input and result output. Perhaps this is due to the reliance on numerical 'black-boxes' to generate computations with little or no requirement for users to truly understand the underlying formulations. Or, perhaps it is the sophisticated, high-resolution graphics that project numerical results which enable users to somehow, perhaps subconsciously, negate the transfer of uncertainty from design input to design output. Failure to recognize design uncertainty can result in unforeseen fatal-flaws pertaining to safety and economics.
A solution to data limitations and parametric uncertainty is systematic model calibration. The back analysis of observed ground reaction is fundamental to achieving confidence in numerical output. Any numerical simulations, with the exception of green-field studies (which must instead rely on thorough sensitivity testing), should have some degree of model calibration. There is a broad spectrum in the level of calibration detail that can be achieved, from qualitative ground response matching to sophisticated quantitative calibration. The rigor and detail of calibration is dictated by the available observations and measures of ground reaction.
This colloquium will address how the state-of-practice in numerical simulations for geomechanical engineering applications must demand model calibration. Using case studies from the field of mining geomechanics, a comprehensive presentation of calibration techniques will be provided for different types of ground reaction data, ranging from qualitative visual observations to quantitative instrumentation and micro-seismic data. Seismic data is arguably one of the most valuable tools for model calibration. This colloquium will also showcase an innovative game-changer in the technical methodology for numerical simulations of induced micro-seismicity.
Dr. Kathy Kalenchuk has a degree in Mining Engineering from the University of Alberta and she completed both her Master's and Doctorate degrees in Geomechanical Engineering at Queen's University. Dr. Kalenchuk has been working in the field of mining geomechanics for 15 years. She is currently a Principal Geomechanics Consultant at MDEng, and provides geomechanical engineering services to mining operations and projects around the world. Dr. Kalenchuk's areas of expertise include both underground and open pit geomechanics, ground support design, slope stability, mine induced seismicity, rock burst risk management and numerical modelling. Dr. Kalenchuk's expertise in high-end numerical modelling, is focused on developing calibrated models capable of reproducing rock mass behaviour as observed through field studies and monitoring instrumentation.