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2005-05-18 - Colloque/Article dans les actes avec comité de lecture - Anglais - page(s)

Germay C., Bette P., Poyol E., Dagrain Fabrice , "Measure of rock mechanical properties from scratching test" in Devex 2005 Featuring Subsurface Techniques to Enhance Recovery, Aberdeen, Ecosse, 2005

  • Codes CREF : Mécanique appliquée générale (DI2100), Bâtiments génie civil transports (DI2600)
  • Unités de recherche UMONS : Génie civil et Mécanique des Structures (F801)
Texte intégral :

Abstract(s) :

(Anglais) Previous papers have been presented strong experimental evidence that rock strength properties can be assessed from “scratch” tests. Experiments indicate that rock cutting is associated with a “ductile” or a “brittle” mode of failure depending on the depth of cut. The ductile mode takes place at shallow depth of cut and is associated with plastic flow, while the brittle mode occurs above a threshold depth of cut and is characterized by the propagation of tensile crack. In the ductile mode, the forces mobilized on the cutting face are found to be proportional to the cross-sectional area of the cut. It was shown that within the ductile regime, the force acting on the cutting face is found to be proportional to the cross-section area of the groove being traced. The coefficient of proportionality called the intrinsic specific energy ? appears well correlated to the uniaxial compressive strength, q, of the material. A portable device was developed at the University of Minnesota in the late 1990’s in order to conduct quick and precise scratch test and measure accurately the magnitude and inclination of the force acting on the cutter. Over the years, the apparatus was improved, the experimental procedure was refined and optimized and numerous tests were conducted on numerous materials: sedimentary rocks but also some construction materials. The paper describes the experimental setup and the methodology. We present results of scratching and uniaxial compression tests carried out in different laboratories, and establish a correlation between ? and q. Finally, we present several practical applications associated to the logging features of the scratch test.