ANISOTROPY OF MECHANICAL PROPERTIES OF GREYWACKE

Abstract

The paper brings the description of the mechanical properties of greywacke sampled in Kobeřice quarry (Lower Carboniferous Culm Basin, Drahany Uplands, Bohemian Massif). Anisotropy of mechanical properties was identified from a series of laboratory tests of oriented samples using the following procedures: (1) indirect tensile testing, (2) uniaxial compressive testing and (3) triaxial compressive testing. Parameters of Mohr-Coulomb and Hoek-Brown failure criteria were determined by the evaluation of the obtained laboratory data. The tested greywacke performed relatively high uniaxial compressive strength, roughly 200 MPa. Better fitting by Mohr-Coulomb criterion was identified than by Hoek-Brown one within the investigated interval of confining stresses (0-15 MPa). In addition, Schmidt hammer test was carried out with a comparison of several correlation relationships to uniaxial compressive strength which was compared with the directly obtained value from laboratory tests.

Keywords

• greywacke
• uniaxial compressive strength
• triaxial compressive strength
• splitting tensile strength
• failure criterion
• schmidt hammer
• correlations