Effect of Anisotropy on Basic and Residual Friction Angles in Schist Rocks

Abstract

The basic friction angle (φb) tests are a common and practical method used to determine the shear strength of discontinuities. Tilt device is generally used in basic friction angle experiments. In this study, the effects of the anisotropy properties of green and mica schist rocks taken from the copper mine site in Kastamonu Hanönü district on the basic and residual friction angles were investigated. For this purpose, experiments with a specially designed tilt device were conducted on dried and saturated green schist and mica schist samples with orientation angles of 0°, 15°, 30°, 45°, 60°, 75° and 90° relative to the loading axis. According to the results in dried and saturated conditions, maximum basic and residual friction angle values were obtained for green schist samples at 60°. The results were close to each other in the experiments carried out in both saturated and dried conditions. Green schist samples were less affected by the saturated media. Mica schist samples were not affected by anisotropy for both media, and close values were obtained in all orientation angles. It was determined that the basic and residual friction angles were lower in saturated conditions compared to dried ones.