Influence of direction of principal elastic axis to principal tensile stress under diametrical compression

In this paper, the distribution of principal tensile stress in an orthotropic rock specimen under a diametrical compression test is shown. This distribution was obtained by calculation using Lekhnitskii's theoretical solution and an additional equation formulated by Kawakubo, et al. Concentrated force was adopted as the boundary condition that can be represented by FEM. Calculation was carried out in several directions along the principal elastic axis. Graphical representations show that the tensile principal stress which occurs in the direction of larger elastic modulus is larger than that which occurred in the direction of the smaller elastic module. They also show that the tensile stress which occurs in the direction perpendicular to the loading direction along the loading radius is the same as the principal tensile stress unrelated to its angle of the direction of principal elastic axis in the loading direction. Finally, the results of this study were compared with those obtained by Claesson et al. and some differences between them are shown in graphical representations. © 2011 ARMA, American Rock Mechanics Association.