Impact of roughness of discontinuities on the behaviour of jointed rock samples

The subject of the publication is the behavior of rock samples faulted by individual discontinuities with different roughness under three-axial compression conditions, with confining pressures up to 30 MPa. Samples with discontinuities oriented at angles of 30°, 45° and 60° in relation to the directions of external loads were prepared for the tests. Before the three-axial compression tests, the discontinuity surfaces were scanned and parameters describing the geometrical structure of these surfaces were determined. It has been shown that the roughness of the discontinuity walls causes a reduction in stiffness and strength. It has also been shown that with the increase of the confining pressure, the strength of the samples increases linearly, and the higher values of the angle at which the discontinuity is oriented corresponds to higher strength.