| Size effect is an essential characteristic of mechanical properties for jointed rock mass, while Representative Elementary Volume (REV) is the critical issue in the research of size effect. Therefore, the deformation and strength parameters’ REV of jointed rock mass and its fractal features are scientifically studied based on size effect of mechanical properties, which provides a significant guidance for choosing medium mechanical model and equivalent mechanical parameters correctly. The main achievements are as follow:Combined digital photogrammetry with mathematical statistics technology, approaches to joint network simulation with different distributions are mainly studied and corresponding programs are developed. Practice shows that the algorithm can generate joint network easily which is equivalent to that of authentic rock mass in statistics.Size effect and anisotropy of deformation and strength parameters of jointed rock mass are mainly studied by numerical analysis method and the REVs of mechanical parameters(Elasticity Modulus Ey, Shear Modulus Gxy and Uniaxial Compression Strength σp) are gained simultaneously. Plenty of numerical tests are performed and computation results clearly indicate that all of mechanical parameters vary with the size of jointed rock mass specimens. But when the size of rock mass specimen is increased to a certain value, they all approach constant values together. Meanwhile, the equivalent flexibility matrix in constitutive relation and the macroscopic strength parameters (c、φ) are calculated.Variation of strength property against fractal dimension of jointed rock mass, including failure mode, is studied in the end. The results indicate that the smaller fractal dimension is, the unevener joint distribute. Uniaxial compressive strength of jointed rock mass increases with the increase of fractal dimension. The relation between fractal dimension and compression strength implies the principle of size effect of jointed rock mass in a way. |
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