Size Effect and Anisotropy in a Transversely Isotropic Rock Under Compressive Conditions

A series of uniaxial and triaxial compression tests were performed on slate samples with different diameters at foliation orientations respect to the direction major principal stress. The size effect anisotropy in slate, as a transversely isotropic rock, investigated, research focused aspects elastic properties, compressive strength (UCS), (TCS), residual (TRS). In five constants for only Young’s modulus parallel plane is dependent. UCS follows descending size-effect model developed from coal. behaviors TCS are similar. Two size-dependent failure criteria proposed by incorporating into modified Hoek–Brown Saeidi verified against experimental data. This first time that relationship among strength, specimen size, orientation confining pressure has been comprehensively captured rock. Without an evident effect, anisotropic TRS also effectively cohesion loss model, two bound equations brittleness index finally work promises provide upscaling method determining mechanical parameters rocks practical engineering.