Mark Diedrichs
About
PhD, Peng, FEIC, ARMA Fellow, FCAE Professor of Geological Engineering, Queen’s University, Kingston, Canada President and Consultant - Innovative Geomechanics Inc.
Dr. Mark Diederichs began his rock mechanics and rock engineering career in 1987, earning a Masters Degree in Geological Engineering in Toronto, Canada. He worked with the Canadian mining sector for a decade providing R&D services in seismic monitoring, rock engineering software development, support design and rockburst research.
He coauthored an industry handbook on mine rock support before embarking on his PhD research related to the mechanics of rock fracture at low confinement. He has been a professor of Geological Engineering at Queen’s University for 24 years. He has been a rock mechanics and engineering geology consultant since the mid 90’s. His industrial rock engineering experience includes site investigation, analysis and design for underground and surface mining, tunnelling in strong and weak rocks, rock burst management and support design, large underground cavern design, nuclear waste repository engineering, hazard assessment and risk management.
At Queen’s University he has supervised over 100 research graduates and co-authored over 450 refereed technical papers. He is also president of Innovative Geomechanics Inc., continuing to provide rock engineering advise and review to the mining, tunnelling and hydropower sectors around the world.
More than Sixty Years of Brittle Damage in Rock Mechanics – the Evolution of Spalling Analysis
While important progress was made in the understanding of brittle fracture in rock, the prediction of rock-bursting in a general setting remained elusive.
In the 1990’s and beyond, with the advent and development of advanced numerical analysis tools, spalling simulation and prediction became a busting research field with many questions to answer with tools both old and new. Why was the in situ rock strength predictably lower than values from lab testing? Why was brittle spalling often locally dramatic but self-limiting in depth? Could the spalling initiation stress be determined from lab testing? How do macroscopic spall fractures propagate more readily in the field than in lab samples? How could the depth of spalling and therefore the extent of strain bursting be assessed?
Many decades of laboratory investigation has led to important damage indicators obtained from conventional testing. For the last 30 years, sophisticated discontinuum and hybrid models have been applied to further understand the process of extensile fracture in massive rock at high stress. Add to this a recent recognition that dilation within this spalling mass as well as confined dilation within the neighboring rock can drive the rockburst process.
This talk will focus on the development of empirical, analytical and numerical spalling analysis and prediction with links to the transition to dynamic rupture and rockbursting. A discussion of challenges still to be solved will round out the journey.