THE SHEAR STRENGTH OF REINFORCED ROCK JOINTS

The evaluation of the shear strength of rock joints, reinforced by means of steel dowels, by both experimental measurements and numerical modelling with the aim of determining a provisional tool for optimization of dowel design is presented. The influence of some important parameters of both the rock and the steel type on the mechanical behaviour of the reinforced structure has been studied. The analysis of the mechanical behaviour of the discontinuous rock mass-dowel system presented in this paper involved the following theoretical and experimental studies: laboratory tests on reinforced rock joints; Finite Element Method (FEM) modelling of the laboratory tests; analytical models for determination of the reinforced joint shear strength; comparison between the experimental and analytical results. The tests have been carried out in order to evaluate the influence of some important parameters on the mechanical behaviour of the reinforced structure: steel type; bar diameter; reinforcement type (bars and tubes); rock material type. Shear resistance is heavily influenced by the quoted parameters. Yielding steel provides the highest contribution to the global reinforced joint shear resistance when using bars or tubes. Stronger and stiffer rock materials lead to higher shear stresses in the steel and consequently lower overall resistance. Two different mechanisms of reinforcement failure have been observed while varying the rock material characteristics. The analytical model has been set up in order to reproduce these two failure mechanisms, one involving a strong and stiff rock material with bar failure determined by shear and tensile stresses at the joint intersection; and the other involving weaker rock and the formation of two symmetric plastic hinges in the bar, with failure being due to either the tensile strength or the ultimate elongation of the reinforcement being reached. Finally, the analytical model has been validated by comparison with experimental results. (A)

  • Availability:
  • Corporate Authors:

    Elsevier

    The Boulevard, Langford Lane
    Kidlington, Oxford  United Kingdom  OX5 1GB
  • Authors:
    • FERRERO, A M
  • Publication Date: 1995-9

Language

  • English

Media Info

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Filing Info

  • Accession Number: 00713433
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Nov 22 1995 12:00AM