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2018-09-18 - Colloque/Abstract - Allemand - page(s)

Wattier Marie-Laure , Vandycke Sara , Gonze Nicolas , Descamps Fanny , Barbier Maxime, Tshibangu Katshidikaya , "Faulting and stability in a chalk quarry" in Engineering in Chalk, Londres, Royaume-Uni, 2018

  • Codes CREF : Prospection minière et pétrolière (DI2321), Sciences de la terre et du cosmos (DI1400), Mécanique des roches (DI1418), Géodynamique et tectonique (DI1433)
  • Unités de recherche UMONS : Génie Minier (F408)
Texte intégral :

Abstract(s) :

(Anglais) Fractures and faulting in Chalk result from a brittle tectonic context leading to structures with preferred definitions and geometries. When quarrying, the geometry of the exploitation should account for the directions of major fractures and faults for stability purposes. A systematic structural survey was performed in a Chalk quarry with localization and measurement of geometry (dip, direction) and classification of fractures. Two major faulting directions are identified, with a high dip angle (above 60°) to the South. 136 faults are identified and well distributed throughout the site. Most of them are normal faults but some strike-slip faults clearly appear. Joints are generally vertical with 2 main directions and a regularly spaced. Structural data are first integrated in a three-dimensional geological and geometrical model of the quarry. This model shows, in some places, that the direction of the bench face and structural features are in condition of developing hazardous slope failure. The structural model is then used for building typical 2D geomechanical models of the behaviour of discontinuities that may induce displacements. Several cases are considered depending on dip, direction and joint properties. The quality of the rock mass is assessed by means of the GSI and RQD indices and mechanical properties are modified accordingly. to the influence of saturation is also considered. The combination of structural and mechanical models helps the quarry managers in optimizing the geometry of their exploitation, particularly to manage potential hazardous areas.