THE EFFECT of ANISOTROPY on the DYNAMIC PROPERTIES of SCHIST ROCKS

Abstract

Dynamic elastic properties of rocks such as modulus of elasticity and Poisson’s ratio are important in some design stages of underground and surface engineering structures. Also, anisotropy is that rocks show different strength and deformation properties with the different orientation angles that they gain as a result of the effect of the direction, fabric, microstructure and discontinuities. Different lithological rock units with anisotropy characteristics are encountered in studies carried out in underground and surface engineering structures, and in cases with such characteristics, there are problems in terms of stability.
In this study, the effect of the anisotropic property of rock masses on elastic parameters such as dynamic young modulus and dynamic Poisson’s ratio were investigated. For this purpose; samples with different orientations were obtained from schists, which are metamorphic rocks, at 0°, 15°, 30°, 45°, 60°, 75° and 90°. Experimental studies were carried out to determine the mechanical and physical properties of these samples. Dynamic young modulus and dynamic Poisson's ratio were determined by P and S velocity of wave propagation experiments. With the results obtained, while the young modulus and Poisson’s ratio of samples belonging to the green schist rock unit with different orientations show a relatively stable structure, these values for the mica schist unit are quite variable and wavy. Therefore, the anisotropy feature of the rock must be taken into consideration in terms of the stability of the structure in engineering studies to be carried out in the mica schist unit.

Keywords

• Anisotropy
• P and S wave
• Rock dynamic properties

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