Abstract

In this study; for a copper mine located in the north of Turkey, the strength of the effect of anisotropy properties of metamorphic rock composed of mica-schist and greenschist was investigated. For this purpose, for core samples which have foliation planes taken as 0°, 15°, 30°, 45°, 60°, 75° and 90° based on the loading axis, unit weight, indirect tensile strength, uniaxial compressive strength and triaxial compressive strength experiments were conducted in dry and saturated conditions. Mica-schist and greenschist showed U type as anisotropic characteristic and a moderate to a high degree of anisotropy structure with calculated anisotropy rates of schists in dry and saturated conditions. In general, mica schist yielded minimum triaxial compressive strength at 30° and maximum triaxial compressive strength at 75° at all confining pressures. The greenschist yielded minimum triaxial compressive strength between 15° and 30° and the maximum triaxial compressive strength between 45° and 75°. In addition, the effect of anisotropic structure on slope stability was investigated. That effect of the anisotropy showed that the factor of safety values varied significantly. Therefore, it was concluded that this feature should not be ignored in rock masses with anisotropic characteristics.

1 Introduction

Anisotropic rocks, unlike rocks with isotropically homogeneous properties, are defined as materials showing different properties based on direction. During the formation of the rocks, bedded rocks are formed in different directions as a result of geological and tectonic effects. Generally, most rock groups are considered anisotropic (Ismael et al. 2017).

The anisotropic effect in rocks is influenced by the micro and macro scale geological features. Geological features in the micro-scale are the fabric structure, texture, schistosity, foliation and cleavage properties of the rock. These features are formed by the primary stresses of the rocks and the influence of the geological structure (Ullemeyer et al. 2006). The geological features on the macro scale are discontinuities such as fractures, cracks, bedding, shear planes and faults. These structures are capable of changing the strength, deformation and similar properties of the rock (Salager et al. 2013; Ramamurthy 1993).

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