Mechanical properties of granulite from Horní Bory in Bohemian massif

Abstract

Granulite represents one of the favourite rock types for the construction of an underground nuclear waste repository in the Czech Republic. Granulite from the Bohemian Massif (locality Horní Bory) was investigated in this study, with a special focus on the evaluation of the rock anisotropy. Investigated rock represents typical fine-grained foliated felsic granulite with principal mineral association: quartz + feldspar (K-feldspar > plag ioclase) + garnet + biotite + kyanite and/or sillimanite. Anisotropy was identified in the rock fabric both at macroscopic and microscopic scale. During the laboratory testing, granulite reached considerable high uniaxial compressive strength (UCS) - up to 240 MPa; and brittle type (Class II) of failure occurred. We found that variability of the UCS and Young's modulus were relatively low. On the other hand, variability of the Poisson's ratio and the constants in Hoek-Brown failure criterion in triaxial loading were significantly high