Three Hinge Buckling Experimental Study

In September 1989, a buckling ("pop-up") failure occurred at Woods Sand and Gravel Quarry in Kingston, ON.This resulted in flooding of the quarry and significant impact on the local groundwater conditions (e.g.neighbouring wells went dry). Buckling failures have commonly arisen in southern Ontario and themid-western U.S. and typically develop suddenly, with little warning, driven by high horizontal in situ stressesin the stiff, laminated, near-surface rock. As a result, the Ontario Ministry of Environment and Climate Change(OMECC) has requested quantifiable assessment of rock buffer thickness (the separation between quarry floorand underlying aquifer) for future quarry development on the basis of fundamental engineering principles andsite-specific conditions. Pop-up buckling, also referred to as three hinge buckling (THB), tends to occurviolently in laminated rock slabs where a central hinge and two abutment hinges are formed. Although manyauthors have made progress in the study of buckling behaviour in rock mechanics, several key issues remainunresolved. There is potential that this licensing requirement, or similar, will arise in other Canadian and U.S.jurisdictions. Given Dexter's stated objective of extending their business interests nationally andinternationally, obtaining a greater understanding of this challenging issue will help to both offset potentialrisks to existing quarry operations and future quarry development opportunities in other jurisdictions. In orderto proactively address this issue, Dexter is initiating a research project to better understand the mechanisms andrisk factors associated with three hinge buckling, and is engaging Dr. Corkum's lab to help conduct thenecessary background research. This proposed research program will involve a laboratory experimentalprogram, supported by numerical modelling (discontinuum), to investigate the THB buckling mechanism. Inaddition, field mapping to quantify geotechnical structural conditions for a quarry in Nova Scotia will beconducted to support translating the laboratory and numerical findings to actual field conditions. The resultswill have practical, directly applicable implications for Dexter, the Canadian mining industry, regulatory