Development Of A 3d Equivalent Continuum Model For Deformation Analysis Of Systematically Jointed Rock Masses

Development of a 3D Equivalent Continuum Model for Deformation Analysis of Systematically Jointed Rock Masses

Deformability of jointed rock masses are potentially anisotropic and non-linear due to existence of the discontinuities intersecting the rock matrix. Models to analysis the deformation of jointed rock masses are divided into two main categories: discontinuum models and equivalent continuum models. Discontinuum models treat the rock mass as an assemblage of intact rock blocks interacting at their boundaries. Discontinuities are simulated explicitly using appropriate contact models. However, when the number of discontinuities in a model increases, the explicit definition of discontinuities become difficult and, in some cases, impractical. Equivalent continuum models provide an alternative to discontinuum models for such cases. In these models, the behaviour of a jointed rock mass is approximated by the analysis of its equivalent continuum. The discontinuities are taken into account implicitly, either by implementing proper constitutive relations or by adopting appropriate mechanical parameters. In this research, the principal deformation mechanisms for a jointed rock mass are defined and characterized by the detailed analysis of the results of a series of plate loading tests conducted on the rock mass. A new three dimensional equivalent continuum model, the JointedRock model, is formulated to simulate the observed deformation mechanisms. The constitutive equations are presented in a tensor form so the model can be applied for any arbitrary spatial configuration of discontinuities. A Mohr-Coulomb failure criterion is used to check failure of intact rock blocks and slip along the rock joints. The JointedRock model is implemented in the finite difference code FLAC3D and is verified against the distinct element method (3DEC) and, where available, analytical solutions. A new method is proposed for interpretation of the results of plate loading tests conducted on jointed rock masses. The method is used to interpret the results of the study tests and to determine the anisotropic deformation modulus of the rock mass.

Applied Mechanics Reviews

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